'xi' definitions:

Definition of 'xi'

From: WordNet
adjective
Being one more than ten [syn: eleven, 11, xi]
noun
The cardinal number that is the sum of ten and one [syn: eleven, 11, XI]
noun
The 14th letter of the Greek alphabet

Definition of 'xi'

From: GCIDE
  • xi \xi\, adj. The Roman number symbolizing the value eleven. Used after a noun it may symbolize the ordinal number; as, Superbowl XI.
  • Syn: eleven, 11. [WordNet 1.5]