Refers to the type of warship. The English loanword is used directly in Japanese.
その海軍は新しいフリゲートを配備した。
The navy deployed a new frigate.
フリゲート is the international classification for a specific size of warship, while 護衛艦 is the general Japanese term used for escort ships of various classes (including frigates) in the Self-Defense Forces.
フリゲート refers to a smaller, lighter warship class, whereas 駆逐艦 (destroyer) is a larger, more heavily armed class that learners often confuse with it.
counter for ships · counter for one half of a pair · counter for bundles (archaic)
frigate (warship)
From English 'frigate'.