名詞 retention:

1. the act of retaining something
   同義詞：keeping, holding
2. the power of retaining and recalling past experience
   同義詞：memory, retentiveness, retentivity
3. the power of retaining liquid
   同義詞：retentiveness, retentivity

re.ten.tion

n.（名詞）

The act of retaining.
保持：保持的行為
The condition of being retained.
保留，滯留：被保持的狀態(tài)
Capacity or power of retaining.
保持力，持續(xù)力
An ability to recall or recognize what has been learned or experienced; memory.
記憶力：記起或認(rèn)識出已經(jīng)學(xué)過或經(jīng)歷過的事物的能力；記憶力
Something retained.
被保持物
Medicine Involuntary withholding of wastes or secretions that are normally eliminated.
【醫(yī)學(xué)】 停滯：正常情況下應(yīng)被除去的廢物或分泌物的不自覺的保留

來源：
Middle English retencioun
中古英語 retencioun
from Old French retention
源自 古法語 retention
from Latin retentiô retentiôn-
源自 拉丁語 retentiô retentiôn-
from retentus [past participle of] retinôre [to retain] * see retain
源自 retentus [] retinôre的過去分詞 [保持] *參見 retain