The Collaborative International Dictionary of English v.0.48:
Fortify \For"ti*fy\, v. t. [imp. & p. p. Fortified; p. pr. &
vb. n. Fortifying.] [F. fortifier, L. fortificare; fortis
strong + -ficare (in comp.) to make. See Fort, and -fy.]
1. To add strength to; to strengthen; to confirm; to furnish
with power to resist attack.
Timidity was fortified by pride. --Gibbon.
Pride came to the aid of fancy, and both combined to
fortify his resolution. --Sir W.
2. To strengthen and secure by forts or batteries, or by
surrounding with a wall or ditch or other military works;
to render defensible against an attack by hostile forces.