词根词缀：a-, an-

【来源及含义】Greek: prefix; no, absence of, without, lack of; not

【相关描述】These prefixes are normally used with elements of Greek origin, a- is used before consonants and an- is used before vowels.

It affects the meanings of hundreds of words.

There are too many words that use these prefix elements to list all of them on this site; however, there are significant examples listed in this and the other units where they exist.

【同源单词】abacterial, abaptism, abarognosis, abasia, abiocoen, abiogenesis

词根词缀：pneumo-, pneum-, pneumono-, pneumon-

【来源及含义】Greek: lung; breath, breathe

【相关词根词缀】 Word units related to breath and breathe: hal-; pneo-; pneumato-; psych-; spiro.

【同源单词】amphipneust, amphipneustic, angiopneumography, apneumia, apneuses, apneusis

词根词缀：-um

【来源及含义】Greek > Latin: a suffix that forms singular nouns

【相关描述】Here are just a few of the hundreds of words that end with -um.

【同源单词】abandum, abortorium, absorption spectrum, acropodium, actinium, acute delirium