From The Collaborative International Dictionary of English v.0.48 [gcide]:
Retention \Re*ten"tion\, n. [L. retentio: cf. F. r['e]tention.
See Retain.]
1. The act of retaining, or the state of being ratined.
[1913 Webster]
2. The power of retaining; retentiveness.
[1913 Webster]
No woman's heart
So big, to hold so much; they lack retention.
--Shak.
[1913 Webster]
3. That which contains something, as a tablet; a ???? of
preserving impressions. [R.] --Shak.
[1913 Webster]
4. The act of withholding; retraint; reserve. --Shak.
[1913 Webster]
5. Place of custody or confinement.
[1913 Webster]
6. (Law) The right of withholding a debt, or of retaining
property until a debt due to the person claiming the right
be duly paid; a lien. --Erskine. Craig.
[1913 Webster]
Retention cyst (Med.), a cyst produced by obstruction of a
duct leading from a secreting organ and the consequent
retention of the natural secretions.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
retention
n 1: the act of retaining something [syn: retention,
keeping, holding]
2: the power of retaining and recalling past experience; "he had
a good memory when he was younger" [syn: memory,
retention, retentiveness, retentivity]
3: the power of retaining liquid; "moisture retentivity of soil"
[syn: retentiveness, retentivity, retention]