backtick

Computing, Engineering, Mathematics, Media, Natural sciences, Physical sciences, Publishing, Sciences, Typography The symbol `, resembling a reversed quotation mark and also being, or being homoglyphic to (depending on mental model), a grave accent mark in isolation. (Common uses include (1) use as a dead key in composing grave-accented characters, (2) use as an escape character to mark literals, and (3) many other uses as defined by contexts.)