em·py·e·ma 
(ĕm′pī-ēmə)
(ĕm′pī-ēmə)n. pl. em·py·e·ma·ta (-mə-tə)
The presence of pus in a body cavity, especially the pleural cavity.
[Medieval Latin empyēma, from Greek empuēma, from empuein, to suppurate; see p- in the Appendix of Indo-European roots.]
em′py·emic adj.