Merriam-Webster Collegiate Dictionary - expression

 noun  Date: 15th century  1.  a. an act, process, or instance of representing in a medium (as words) ; utterance freedom of ~  b.  (1) something that manifests, embodies, or symbolizes something else this gift is an ~ of my admiration for you  (2) a significant word or phrase  (3) a mathematical or logical symbol or a meaningful combination of symbols  (4) the detectable effect of a gene; also expressivity 1  2.  a. a mode, means, or use of significant representation or symbolism; especially felicitous or vivid indication or depiction of mood or sentiment read the poem with ~  b.  (1) the quality or fact of being expressive  (2) facial aspect or vocal intonation as indicative of feeling  3. an act or product of pressing out  • ~al adjective