of or pertaining to a texture in which the groundmass is characterized by closely packed, short, quadrilateral crystals of feldspar larger than those in a trachytic groundmass
Word origin
[ortho- + -phyre + -ic]ortho- is a combining form occurring in loanwords from Greek, where it meant “straight,”“upright,” “right,” “correct” (orthodox) and on this model used in the formation of compound words (orthopedic). Other words that use the affix ortho- include: orthodox, orthogonal, orthohydrogen, orthokeratology, orthophosphoric acid; -ic is a suffix forming adjectives from other parts of speech, occurring originally inGreek and Latin loanwords (metallic; poetic; archaic; public) and, on this model, used as an adjective-forming suffix with the particular senses“having some characteristics of” (opposed to the simple attributive use of the basenoun) (balletic; sophomoric); “in the style of” (Byronic; Miltonic); “pertaining to a family of peoples or languages” (Finnic; Semitic; Turkic)