semi-infinite

Adjective

 * 1)  Involving a finite number of variables but an infinite number of constraints, or vice versa.
 * 2)  Sufficiently thick that the level of penetration of a projectile is not affected by its thickness.
 * 3) Limited at one end but extending to infinity in the other direction.

Usage notes

 * semi-infinite is several times more common than semiinfinite in print. GPO manual recommends using a hyphen to avoid doubling a vowel except after short prefixes.