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：vid-, video-, vis-, -vision, -visional, -visionally, visuo-, vu-

【来源及含义】Latin: videre, "to see"; plus words with other related meanings: to notice, noticing, noticed; observe, observing, observed; look, looking, looked; perceive, perceiving, perceived, perception; see, seeing, saw, seen, sight; view, viewing, viewed; manifest, manifesting, manifested; reveal, revealing, revealed, revelelation

【相关描述】Although many of the words in this unit seem to be from other Latin origins, all of them are etymologically derived from the main Latin videre, "to see" element.

【相关词根词缀】 Cross references of word families that are related directly, or indirectly, to: "appear, visible, visual, manifest, show, see, reveal, look": blep-; delo-; demonstra-; opt-; -orama; pare-; phanero-; phant-; pheno-; scopo-; spec-; vela-, veal-.

【同源单词】achromatic vision, advice, advisability, advisable, advisableness, advisably