Literal physical use: to make two things hit against each other, or to have weapons or similar objects clash. Less common in everyday use than the planning or discussion sense.
At the toast, everyone lightly clinked their glasses together.
2
ichidan verb, transitive verb
discuss in advance; coordinate; arrange beforehand
Common business and everyday use for confirming plans, procedures, details, or roles in advance. Often takes the thing to be discussed with を and the person with と.