The prosodic word (ω-word), the first interface level with morphosyntactic constituents, is introduced. The chapter starts with monomorphemes and shows that lexical words are ω-words: They have a minimal weight (i.e., they are minimally bimoraic). By contrast, function words are usually not ω-words: When unfocused they are often pronounced in their reduced form and do not carry lexical stress. A review and OT analysis of the defective distribution of the inflectional prefix ge- is provided. The rest of the chapter is concerned with derivation and compounding. A distinction is made between concatenative and non-concatenative prosodic morphology. In the former, complex words are built in a recursive fashion and the morphemes can be ω-words themselves or not, the result is always a ωmax. Culminativity and syllable structure are indicators of prosodic words, as is their faculty of being elided in coordination. It is shown that inflection and part of derivation are non-moraic and do not form prosodic words, while another part of derivation and all elements of compounds always form distinct prosodic words. An OT analysis is developed that takes into account all aspects of prosodic words.