one's nature / characteristic / sex, gender / content

the nature of something

-ity, -ness, the nature of quality or something

one's nature / characteristic

interstellar

interleaf / slip sheet

(anatomy, attributive) interosseousness or interosseality

(uncommon) morning

by chance, incidentally

(typography) an intercharacter space, the white space between the bottom/right edge of one character and the top/left edge of the next character, corresponding to "tracking" in Western typography