Word forms: plural suffixes1. countable nounA suffix is a letter or group of letters, for example '-ly' or '-ness', which is added to the end of a word in order to form a different word, often of a different word class. For example, the suffix '-ly' is added to 'quick' to form 'quickly'. Compare affix and , prefix.
2. countable nounA suffix is one or more numbers or letters added to the end of a code number to indicate, for example, what area something belongs to.
These ships were all numbered with the suffix LBK.