a·pos·tro·phe 1 
(ə-pŏstrə-fē)
(ə-pŏstrə-fē)n.
The superscript sign ( ' ), usually used to indicate the omission of a letter or letters from a word, the possessive case, or the plurals of numbers, letters, and abbreviations.
[French, from Late Latin apostrophus, from Greek apostrophos, from apostrephein, to turn away : apo-, apo- + strephein, to turn; see streb(h)- in the Appendix of Indo-European roots.]
ap′os·trophic (ăp′ə-strŏfĭk) adj.