Is it past tense or passed tense?

Is it past tense or passed tense? The word past can be used as an adjective, a preposition, a noun, or an adverb. The word passed is the past tense of the verb pass. Both words have many uses. When past is used as an adjective it refers to a time gone by or something from, done, or used in an earlier time.

The word past can be used as an adjective, a preposition, a noun, or an adverb. The word passed is the past tense of the verb pass. Both words have many uses. When past is used as an adjective it refers to a time gone by or something from, done, or used in an earlier time.