Real Dictionary

expression
a measure of the relative size of two classes expressible as a proportion [...]
a plastic container for magnetic tape, as one inserted into a tape deck [...]
a series of observations, measurements, or facts; information [...]
a side view, outline, or representation of an object, esp of a human face or head [...]
a small circle of bacterial DNA that is independent of the main bacterial chromosome. Plasmids often contain genes for drug resistances and can be transmitted between bacteria of the same and different species: used in genetic engineering [...]
a variable quantity, such as force, that has magnitude and direction and can be resolved into components that are odd functions of the coordinates. It is represented in print by a bold italic symbol: F or ̄F [...]
an analysis, esp a determination of the amount of metal in an ore or the amounts of impurities in a precious metal [...]
an arrangement of repeated or corresponding parts, decorative motifs, etc [...]
something formulated or built systematically [...]
the act or an instance of transforming ideas into words [...]
the act or fact of changing or being changed [...]
the act or process of regulating [...]
the desirability of a thing, often in respect of some property such as usefulness or exchangeability; worth, merit, or importance [...]
the division of a physical or abstract whole into its constituent parts to examine or determine their relationship or value [...]
the quality of being stable [...]
Your expression is the way that your face looks at a particular moment. It shows what you are thinking or feeling.
uncountable noun: Expression is the showing of feeling when you are acting, singing, or playing a musical instrument.
variable noun: The expression of ideas or feelings is the showing of them through words, actions, or artistic activities.