Incidents of gender-bending are classified into the following categories:
Applies to derivative and alternate universe works only. Indicates a story which explores how things might differ had the given character been born the opposite gender.
This category is primarily for songs and refers to an incident where a cover of a song explores the same event(s) from another gender perspective.
The character is androgynous enough that they unintentionally get mistaken for the opposite sex as a significant plot point.
A male and a female character trade bodies, whether voluntarily or involuntarily.
The character in question is an opposite-gender clone with memories from the original.
This should be fairly obvious. The only notable point is that this definition is based on the effect on other people, so it can be accidental.
The character in question has a complete set of both male and female sexual organs. (Fiction's interpretation of hermaphroditism)
The character in question appears to be the opposite sex (whether voluntarily or not) without altering their physical form. This may or may not include cross-dressing but generally involves science fiction or magic.
The character in question meets the real-world definition of intersexuality. (eg. AIS, real-world hermaphroditism, etc.)
A character with multiple personalities where not all are of the same gender.
Typically, this means transformation of just the genitals, everything but the genitals, or the addition of breasts to an otherwise male body. (Usually for comedic purposes)
This category is primarily for songs and indicates situations where the lyrics are in disagreement with the singer's voice over the subject's gender.
A variation on body swapping where a deceased or otherwise disembodied character occupies a freshly-vacated body of the opposite gender.
Surgical gender-reassignment. Unlike "Transformation" this keyword indicates that the change bears all the limitations of modern gender-reassignment surgery.
A male and a female character time-sharing a variable-form body
Transformation from male to female or vice-versa, whether scientific or magical in nature.
A person whose instinctual gender identity does not match their physical sex. Usually implies what other characters see as cross-dressing.