ir-1

1.
variant of in-2. (by assimilation) before r: irradiate.

ir-2

1.
variant of in-3. (by assimilation) before r: irreducible.
British Dictionary definitions for ir-

in-1

prefix
1.
not; non-: incredible, insincere, illegal, imperfect, irregular Compare un-1
Word Origin
from Latin in-; related to ne-, nōn not

in-2

prefix
1.
in; into; towards; within; on: infiltrate, immigrate
2.
having an intensive or causative function: inflame, imperil
Word Origin
from in (prep, adv)

ir-

prefix
1.
a variant of in-1 , in-2
Word Origin and History for ir-

assimilated form of Latin prefixes in- (see in-) before -r-.

ir- in Medicine

ir- 1
pref.
Variant of in-1.

ir- 2
pref.
Variant of in-2.