Vaisesika Sūtra 7.2.18

शब्दार्थवसम्बन्धौ ॥१८॥

śabdārthavasambandhau ॥18॥

[शब्द (śabda) - word; अर्थ (artha) - meaning; व (va) - and; सम्बन्धौ (sambandhau) - connections;]

There is a connection between a word and its meanings.