Demigender (from demi "half" + "gender") is an umbrella term for nonbinary gender identities that have a partial connection to a certain gender. This includes the partly female identity demigirl, and the partly male identity demiboy. There are other partial genders using the "demi-" prefix for the same reasons. For example, deminonbinary, demifluid, demiflux, and so on. Like nonbinary, demigender is also an identity within itself, for people who feel connection to the concept of gender rather than certain genders. Being a demigender "is not dependent on how much (as in percentage) someone identities as one gender; it solely depends on if a person identifies as partially. For some, they may identify with two or more genders while others may not."
A demigirl is someone who only partially (not wholly) identifies as a girl or woman, whatever their assigned gender at birth. They may or may not identify as another gender in addition to feeling partially a girl or woman. May also use the terms demigal, demifemale or demiwoman.
Alternatively, demigirl can be used to describe someone assigned female at birth who feels but the barest association with that identification, though not a significant enough dissociation to create real physical discomfort or dysphoria, or someone assigned male at birth who is trans feminine but not wholly binary-identified, so that they feel more strongly associated with “female” than “male,” socially or physically, but not strongly enough to justify an absolute self-identification as "woman".
A demiboy, also called demiguy, is someone whose gender identity is only partly male, regardless of their assigned gender at birth. They may or may not identify as another gender in addition to feeling partially a boy or man. They may also define their identity as both male and genderless (agender).
Alternatively, demiguy can be used to describe someone assigned male at birth who feels but the barest association with that identification, though not a significant enough dissociation to create real physical discomfort or dysphoria, or someone assigned female at birth who is trans masculine but not wholly binary-identified, so that they feel more strongly associated with 'male' than 'female,' socially or physically, but not strongly enough to justify an absolute self-identification as 'man'.
Deminonbinary, or demienby, is a gender identity for someone who partially identifies as nonbinary.
Demifluid is a gender identity for "someone whose gender is partially fluid (genderfluid) with the other part(s) being static; an example could be: one part of their gender is 'woman' while the part that fluctuates is 'man' and 'genderqueer'." In other terms, one part of the gender is static while the other part changes between genders.
Demiflux is a gender identity for "someone whose gender is partially fluid with the other part(s) being static; this differs from 'demifluid' as '-flux' indicates that one of the genders is neutral; an example could be: one part of their gender is 'genderqueer' while the part that fluctuates is 'agender' and 'woman'." In other terms, one part of the gender is static while the other fluctuates in intensity; for example, one part of the gender is 'genderqueer' and the other is 'woman' of fluctuating intensity.
Notable demigender people
There is more information about this topic here: notable nonbinary people
There are many more notable people who have a gender identity outside of the binary. The following are only some of those notable people who specifically use the words "demiboy," "demigirl," or very similar words for themselves.
- Irish journalist Kay Cairns identifies as a genderqueer demiguy.
- American romance author Chelsea M. Cameron identifies as a demigirl.
- Author Kacen Callender is a demiboy.
- Dr. Sand Chang uses a number of varying gender terms for themself, including demiboy.
- Sam de Leve is an American who plays non-binary characters for the Geek & Sundry  and Saving Throw multimedia networks. They are also a dancer  and writer . They describe themself as a "half-boy" in their Twitter bio.
- Indian activist Dan Rebello is a demiboy.
Demigender characters in fiction
There are many more characters in fiction who have a gender identity outside of the binary. The following are only some of those characters who are specifically called demigender, demigirl, demiboy, or similar, either in their canon, or by their creators.
- In School Spirit: An Unlikely Webseries, the character Charley Condomine is demigender.
- Felix Ever After stars a demiboy and was written by Kacen Callender who is a demiboy as well.
- In the dating sim game The Office Type (scheduled for autumn 2020 release), the character Cal is a demigirl and the character Syl is a demiboy.
On August 12, 2010, user Bad Patient of AVEN's transyadas posted
I've been thinking. (It's a thing I do. Pretty much all I do, really.) Last night I was lying in bed and thinking about the kind of stuff everyone else thinks about before they fall asleep: my weird sexual and gender identity. At one point I remembered my fondness of the term "demiromantic" and, chuckling, I said to myself that I can any word relate to me if I just stick a "demi-" in front of it. And then I realised that it might actually help me find a word for my gender identity. I've felt for some time that I may have too much of the masculine element in me to call myself agender and feel good about it — so maybe it would be a nice idea to call myself a demiguy. Demidude. Demibloke. Just not demiman, tyvm, because I only accept being called a man when you're talking about my body and not mind, and even then I prefer adjectives like "masculine" or "male" to that dreaded noun. Now, I'm not being entirely serious here, as I'm not going to go around calling myself a demibloke and I don't think I'll ever find a term that fully describes me anyway — and if I do, my identity will probably change just to spite me — but I kind of like those words and feel that they may actually describe me quite well. I'm not sure. But then again, I'm never sure of anything related to myself.
Bad Patient the DemiyadaPS The elitist douche in me likes describing himself with terms that are likely used by no-one else. 
In December of that year, a different user in that forum, seeking more information, wrote that the only place they could find a description of the term "demigirl" was on the yada wiki. In response, user A Long Time Ago posted
As far as I know, that and demiguy are terms made up by the yadas, so there is no additional information on it. Hopefully, they will get onto the Definitions Master List soon where the terms will get more visibility and then maybe it will spread out into more common usage. I personally identify as demigirl because I feel kind of like an female-agender blend by which I mean that I have no identification as male but have an identification as female that is not very strong.
By Oct 14, 2011, "demigirl" and "demiguy" had been added to the Genderqueer Identities & Terminology page of the popular blog Genderqueerid.. The blog owner, Marilyn Roxie, had collected data for a survey of genderqueer people that year, (Sept 15th - Oct 15th); nine people selected the "demiboy" checkbox, and seven people selected "demigirl."
A tumblr blog named demigenders was started in March 2014, aiming to be "a safe space for those who identify as demigirl, demiboy, demienby, demigender demiflux, or demifluid". Another blog, demigenderpalace, was created in June 2014, with a similar aim.
In 2015, tumblr user transrants created "demigirl & demiguy flag proposals" which would go on to become the standard flags for these identities. User druxydeity created the deminonbinary flag following the same pattern.In 2018, Washington state began to allow "X" gender markers on official documents, with the law stating that
|«||"X" means a gender that is not exclusively male or female, including, but not limited to, intersex, agender, amalgagender, androgynous, bigender, demigender, female-to-male, genderfluid, genderqueer, male-to-female, neutrois, nonbinary, pangender, third sex, transgender, transsexual, Two Spirit, and unspecified.||»|
|See also a blog post about this topic on our Tumblr.|
- Savage (11 November 2014). "Demigender Definitions". A Safe Place for Demigenders. Retrieved 30 April 2020.
- http://www.asexuality.org/en/topic/55798-definitions-master-list/ AVEN: Definitions Master List
- "Some Genderqueer Identities". Gender Queeries. Retrieved 30 April 2020.
- http://asexualityorg.proboards.com/index.cgi?board=gender&action=print&thread=9 Definitions Master List
- McGuire, Peter (9 November 2015). "Beyond the binary: what does it mean to be genderfluid?". The Irish Times. Retrieved 30 April 2020.
- O'Callaghan, Helen (3 October 2015). "Gender fluidity: Break free from being identified as male or female". Irish Examiner. Retrieved 30 April 2020.
- Chelsea M. Cameron [@chel_c_cam] (May 9, 2017). "I've been: bisexual, gay, queer, queer/bisexual. I'm also still not super sure about my gender, but for now demigirl is how I identify" – via Twitter.
- @kacencallender (October 13, 2019). "I'm the demiboy of my dreams, honestly" – via Twitter.
- Kramer, Kaiya (11 December 2015). "Ep 69 Dr. Sand Chang Licensed Psychologist Interview". The Queer Life Radio. Retrieved 6 April 2020.
- Pundir, Pallavi (4 February 2020). "What it's Like Being Non-Binary in India, Where Everyone Uses Gendered Pronouns". Vice. Retrieved 8 November 2020.
- "Charley Condomine". LezWatch.TV. Retrieved 16 June 2020.
- spyro (17 June 2014). "Hello this is the demigender palace". safe space for demigenders. Retrieved 5 July 2020.
- Jackman, Josh (5 January 2018). "Washington to recognise third gender in groundbreaking move". PinkNews. Retrieved 14 May 2020.
- "WAC 246-490-075: Changing sex designation on a birth certificate". Washington State Legislature. Retrieved 14 May 2020.
- Bluebolt712 (15 December 2021). "(Post 1/4) Today is Demigenders Awareness and Pride Day. This is a day I created because I noticed the sharp increase in the number of people claiming these labels as their own in the past few years. Yet, the awareness of demigenders remains quite low". Retrieved 15 December 2021.
- Bluebolt712. "Demigenders Resources". Bluebolt712's LGBT+ Resources. Retrieved 15 December 2021.