From Longman Dictionary of Contemporary English:

noun [countable]

a single group of letters that are used together with a particular meaning

From Longman Dictionary of Contemporary English:

adjective

a regular verb changes its forms in the same way as most verbs, for example its past tense and past participle end in ‘ed’.

From Cambridge Dictionary:

noun

(also the simple past)

the form of a verb used to describe an action that happened before the present time and is no longer happening. It is usually made by adding -ed:

The past simple of 'cook' is 'cooked'.

noun

a verb in which the past tense is not formed by adding the usual -ed ending. Examples of irregular verbs are sing (past tense sang); feel (felt); and go (went).

From Longman Dictionary of Contemporary English:

noun [countable]

the form of a verb used with the verb ‘to have’ in perfect tenses (for example ‘eaten’ in ‘I have eaten’), or with the verb ‘to be’ in the passive (for example ‘changed’ in ‘it was changed’), or sometimes as an adjective (for example ‘broken’ in ‘a broken leg’)