noun

1. a pressing out or squeezing out, as of juice
2. a putting into words or representing in language
3. a picturing, representing, or symbolizing in art, music, etc.
4. a manner of expressing; esp., a meaningful and eloquent manner of speaking, singing, etc. to read with expression
5. a particular word, phrase, or sentence “catch cold” is an idiomatic expression
6. a showing of feeling, character, etc. laughter as an expression of joy
7. a look, intonation, sign, etc. that conveys meaning or feeling a quizzical expression on the face
8. a symbol or set of symbols expressing some mathematical fact, as a quantity or operation
9. a showing by a symbol, sign, figures, etc.
10. Genetics the manifestation of a trait caused by a particular gene

Etymology: ME expressioun < L expressio < expressus: see express