Strong's Concordance G1858

Original Word: ἑορτάζω
Transliteration: heortázō
Phonetic Spelling: heh-or-tad'-zo
[ἑορτάζω] from G1859; to observe a festival

Usages throughout the bible

1 Corinthians 5:8 - Therefore let us keep the feast, G1858 not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth.