What does "triglyph" mean?

Triglyph: An ornament in the frieze of the Doric order, repeated at equal intervals. Each triglyph consists of a rectangular tablet, slightly projecting, and divided nearly to the top by two parallel and perpendicular gutters, or channels, called glyphs, into three parts, or spaces, called femora. A half channel, or glyph, is also cut upon each of the perpendicular edges of the tablet. See Illust. of Entablature.