To enter something (especially a profession) without having planned it.(verb)
To be classified as; to fall under.(verb)
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Use "fall into" in a sentence
"Their counterparts may be seen today in the wild scenes of excitement so common in the religious revivals of certain sects, where the believers, under the influence of noisy, soul-stirring exhortations, become seized with religious frenzy, dance, shout, fall into cataleptic fits, and think they see visions and hear Divine assurances of being saved."
"My doctor and I knew that eventually I would fall into one of these autoimmune-disease categories, but meanwhile there was nothing we could do to keep my body from attacking itself."
"She pointed out that two-thirds of those going unscreened fall into the lower-income population."