n.
Pronunciation: ' pen-ti- ˌ ko ̇ st, - ˌ käst
Function: noun
Etymology: Middle English, from Old English pentecosten, from Late Latin pentecoste, from Greek pent ē kost ē , literally, fiftieth day, from pent ē kostos fiftieth, from pent ē konta fifty, from penta- + -konta (akin to Latin intransitive verb ginti twenty) ― more at VIGESIMAL
Date: before 12th century
1 : SHABUOTH
2 : a Christian feast on the seventh Sunday after Easter commemorating the descent of the Holy Spirit on the apostles ― called also Whitsunday