firm

(transitive) To make firm or strong; fix securely.

(transitive) To make compact or resistant to pressure; solidify.

(intransitive) To become firm; stabilise.

(intransitive) To improve after decline.

(intransitive, Australia) To shorten (of betting odds).

(transitive, UK, slang) To select (a higher education institution) as one's preferred choice, so as to enrol automatically if one's grades match the conditional offer.