词根词缀：acantho-, acanth-, -acanth, -acanths, -acanthid, -acanthous

【来源及含义】Greek: used either as a prefix or as a suffix; pointed appendages; spine, spiny; thorn, thorny

【同源单词】acanth, acantha, acanthaceous, acanthamebiasis, acanthamoeba, acanthesthesia

词根词缀：tetra-, tetr-

【来源及含义】Greek: four; a number used as a prefix

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

【同源单词】rotundo-tetragonal, tessaraglot, tetrabasic, tetrablastic, tetrabrach, tetrabrachius