Formative \Form"a*tive\, n. (Gram.)
   (a) That which serves merely to give form, and is no part of the radical, as the prefix or the termination of a word.
   (b) A word formed in accordance with some rule or usage, as from a root.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Formative \Form"a*tive\, a. [Cf. F. formatif.]

1. Giving form; having the power of giving form; plastic; as, the formative arts.

The meanest plant can not be raised without seed, by any formative residing in the soil. --Bentley.

2. (Gram.) Serving to form; derivative; not radical; as, a termination merely formative.

3. (Biol.) Capable of growth and development; germinal; as, living or formative matter.

Source: Webster's Revised Unabridged Dictionary (1913)