This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Marking the 50th anniversary of an event.

n. A 50th anniversary or its celebration.

adj. Occurring every 50 years

n. A 50th anniversary.

adj. Of or pertaining to half of a century, or a period of fifty years.

n. A fiftieth anniversary.

Occurring at the end of, or celebrating the completion of, fifty years, or half a century: as, a semi-centennial celebration.

n. A semi-centennial celebration.

adj. of or relating to or marking the 50th anniversary

n. the 50th anniversary (or the celebration of it)

"It is against the law, but conformable to usage, and the wedded pairs are subject only to a semicentennial ejection, so that I do not know where a young literary couple could more charmingly begin their married life."

anniversary    day of remembrance