1. to enlarge in discourse or writing; be copious in description or discussion: to expatiate upon a theme.History: 1530–40; < L expatiātus ptp. of ex(s)patiārī to wander, digress, equiv. to ex- + spatiārī to walk about, deriv. of spatium
2. Archaic. to move or wander about intellectually, imaginatively, etc., without restraint.
Webster's Revised Unabridged Dictionary (1913)
A good writer will endeavor to not "increase in size or bulk" but will seek "an enlargement of views, of knowledge, of affection." And endeavor to "release onself from confinement" of thinking.(n.)
The act of increasing in size or bulk, real or apparent; the state of being increased; augmentation; further extension; expansion.
(n.)
Expansion or extension, as of the powers of the mind; ennoblement, as of the feelings and character; as, an enlargement of views, of knowledge, of affection.
(n.)
Diffusiveness of speech or writing; expatiation; a wide range of discourse or argument.
(n.)
A setting at large, or being set at large; release from confinement, servitude, or distress; liberty.