en / Indo-European roots
Examples of words with the root en: and, atoll, ben, bilander, dedans, dysentery, en-, endo-, enkephalin, enter, entero-, enteron, ento-, entrails, episode, esoteric, esotropia, exenterate, in, in-, indigent, inn, inner, inter-, interim, interior, internal, intestine, intima, intimate.
▲ Derivatives include inner, entrails, industry, dysentery.
a. in1 (preposition), from Old English in, in;
b. in1 (adverb), from Old English inn, into, inne, inside;
c. inn from Old English inn, habitation, inn;
d. tsimmes from Old High German in, in;
e. inner from Old English innera, farther in, inner, from Germanic (comparative) *inn(e)ra;
f. (i) ben from Old English binnan, within; (ii) bilander from Middle Dutch binnen, within (be, by; see ambhi + innan, in, within). Both
(i) and (ii) from Germanic *innan. a-f all from Germanic *in..
2. en-1, in-2 from Latin in, in-, in, into.
3. en-2; enkephalin, parenchyma, parenthesis from Greek en, en-.
4. Suffixed form *en-t(e)ro-.
a. intro-; introduce, introit, intromit, introrse, introspect from Latin intrō, inward, within;
b. enter, intra-; intrados from Latin intrā, inside, within;
c. interim, intrinsic from Latin interim, meanwhile, with ablative suffix -im, and intrīnsecus, on the inside, from int(e)rim + secus, alongside (see sekw-1).
5. Suffixed form *en-ter. entrails, inter-, interior, intern, internal from Latin inter, inter-, between, among.
6. intima, intimate2 from Latin (superlative) intimus, innermost (*-mo-, superlative suffix).
7. Extended form *en-do.
a. industry from Latin industrius, diligent (Archaic Latin indostruus; *stru-, to construct; see ster-2);
b. indigent from Latin indigēre, to be in need (egēre, to be in need). Both a and b from indu-, within, from Archaic Latin endo;
c. endo- from Greek endon, endo-, within.
8. Suffixed form *en-tos.
a. dedans, intestine, intine, intussusception from Latin intus, within, inside;
b. ento- from Greek entos, within.
9. Suffixed form *en-tero-.
a. enteric, entero-, enteron; dysentery, exenterate, mesentery from Greek enteron, intestine;
b. atoll perhaps ultimately from Sanskrit antara-, interior.
10. Extended form *ens.
a. episode from Greek eis, into;
b. suffixed form *ens-ō. esoteric, esotropia from Greek esō, within.
11. Possibly suffixed zero-grade form *n̥-dha. and from Old English and, and, from Germanic *anda, *unda.
[Pokorny 1. en 311.]