词根词缀：in-2

【来源及含义】Latin: in, into, within, inside, on, toward [il-, ir-, im-], in, into, etc.: include, incur, invade; also, used intensively, as in the words inflame and inflammable, or without perceptible force.

【相关描述】The in- changes or is assimilated to il- before l, as with "illuminate", to im- before b, as with "imbibe"; before m, as with "immediate"; before p, as with "implant"; and to ir- before r, as with "irrigate".

The form generally remains unassimilated in words formed in English; such as, inbreed.

Don't confuse this in-², meaning "in, into, within", etc. with the Latin prefix in-¹ meaning "not" nor with the prefix for English-origin words in-³ meaning "in, into; within".

【同源单词】illuminate, imbibe, immigrate, import, inaugurate, incalescent

词根词缀：radio-, radi-, rad-

【来源及含义】Latin: ray, radiating [the Latin word for the spokes of a wheel is radius]; spoke, staff, rod

【同源单词】involuntary euthanasia, irradiance, irradiant, irradiate, radial, radian