What is the meaning of -aid?

your ... -s (second-person singular informal, multiple possessions)

forms class A I verbs from nouns and adjectives

forms a third-person singular absolute verb ending in the present indicative and subjunctive and in the future

forms a second-person plural present indicative conjunct verb ending in the present indicative and subjunctive, in the imperative, in the future and in the preterite

alternative form of -id (agentive suffix) used after a broad consonant

Forming nouns denoting the amount contained, -ful

Forms plural nouns., -s

plural of -ad

Source: wiktionary.org