a small pyramid, esp one on top of an obelisk or a larger pyramid
2. crystallography obsolete
a solid figure formed from a polyhedron by placing a small pyramid on each face of the polyhedron
pyramidion in American English
(ˌpɪrəˈmɪdiən, -ˌɑn)
nounWord forms: plural-midia (-ˈmɪdiə)
a miniature pyramid, as at the apex of an obelisk
Word origin
[1830–40; ‹ NL, equiv. to pȳramid-pyramid + -ion dim. suffix ‹ Gk]This word is first recorded in the period 1830–40. Other words that entered Englishat around the same time include: ante, grid, paraffin, stroboscope, walkover