T S Eliot's quirky figure of speech

• Ironical understatement
• Understatement for rhetorical effect (especially when expressing an affirmative by negating its contrary)
• "Not too bad" for "very good"
• Understatement for effect
• Figure of speech like "not unlike"
• 'Not unhappy,' e.g

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Meiosis \Mei*o"sis\ (m[-i]*[=o]"s[i^]s), n. [NL., fr. Gr. mei`wsis, fr. meioy^n to make smaller, from mei`wn. See Meionite .] (Rhet.) Diminution; a species of hyperbole, representing a thing as being less than it really is; understatement; see also litotes ...

Wikipedia Word definitions in Wikipedia
In rhetoric , litotes (, or ) is a figure of speech wherein understatement is used to emphasize a point by stating a negative to further affirm a positive, often incorporating double negatives for effect. For example, "She's not bad looking" could be used ...

WordNet Word definitions in WordNet
n. understatement for rhetorical effect (especially when expressing an affirmative by negating its contrary); "saying `I was not a little upset' when you mean `I was very upset' is an example of litotes" [syn: meiosis ]