词根词缀：bi-, bin-, bino-, bis-

【来源及含义】Latin: two, twice, double, twofold; a number; it normally functions as a prefix

【相关描述】This bi- is used before s, c, or a vowel. Don't confuse this bi- with another one which means "life".

All words except biennial referring to periods of time and prefixed by bi- are potentially ambiguous. Since bi- can be taken to mean either "twice each" or "every two", a word like "biweekly" can be understood as "twice each week" or "every two weeks".

【同源单词】biacid, biangular, biannual, biannual, biarchy, biarticulate

词根词缀：quatr-, quart-

【来源及含义】Latin: fourth, four

【相关词根词缀】 Cross references of word families that are related, partially or totally, to: "four, fourth": quadri-; tessara-; tetra-.

【同源单词】biquarterly, quart, quartan, quartation, quarte, quarte