a symbol (∼) indicating equivalency or similarity between two values.
an exclamation point.
a short oblique stroke (/) between two words indicating that whichever is appropriate may be chosen to complete the sense of the text in which they occur:
one of two marks « or » used in French, Italian, and Russian printing to enclose quotations.
O.E. under licgan "to be subordinate to, to submit to;" see under + lie (v.2). Meaning "to lie under or beneath" is attested from 1600; fig. sense of "to be the basis of" is attested from 1852 (implied in underlying).