A linguistic form which is never spoken alone is a 'bound' form; all others[...] are 'free' forms.
- Bloomfield (1935), Pag. 160

Forms which occcur as sentences are 'free forms'.
- Bloomfield (1935), Pag. 178

The free forms (words and phrases) of a language appear in larger free forms (phrases), arranged by taxemes of modulation, phonetic modification, selection, and order.
- Bloomfield (1935), Pag. 184