词根词缀：centro-, centr-, centri-, kentro-

【来源及含义】Greek > Latin: center; middle point, mid point; focus, focal point, focalize; zero in on

【相关描述】This element originally meant "sharp point, goad" or "spur".

【同源单词】acentric, acentric, acrocentric, allocentric, ambulatory surgery center, amphicentric

词根词缀：ex-, ec-, e-

【来源及含义】Greek: out of, out, outside; away from; used as a prefix

【相关描述】This is a prefix that is supposed to be used with words or roots of Greek origin. The ex- form is used before vowels or h; ec- goes before consonants.

【同源单词】acentric, eccentric, eccentric, eccentric vision, eccentricity, ecclesia

词根词缀：-ity

【来源及含义】Latin: suffix used to form abstract nouns expressing act, state, quality, property, or condition corresponding to an adjective

【同源单词】abnormality, absorbability, acclivity, acerbity, acridity, acrity