ob-

prefix (also oc- before c, of- before f, op- before p) occurring mainly in words of Latin origin, meaning:
1 exposure, openness (object; obverse).
2 meeting or facing (occasion; obvious).
3 direction (oblong; offer).
4 opposition, hostility, or resistance (obstreperous; opponent; obstinate).
5 hindrance, blocking, or concealment (obese; obstacle; occult).
6 finality or completeness (obsolete; occupy).
7 (in modern technical words) inversely; in a direction or manner contrary to the usual (obconical; obovate).
Etymology: L f. ob towards, against, in the way of

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prefix

Etymology: Middle English, from Old French, from Latin, to, toward, against, over, completely, from ob to, before, against, on account of — more at epi-

1. : inward

obimbricate

2. : incompletely

obrotund

obround

3. : in reverse order

obdiplostemonous

4. : inverse

obovate

obconic

obcordate

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a prefix meaning "toward," "to," "on," "over," "against," orig. occurring in loanwords from Latin, but now used also, with the sense of "reversely," "inversely," to form Neo-Latin and English scientific terms: object; obligate; oblanceolate.

Also, o-, oc-, of-, op-.

[ME ( < OF) < L, repr. ob (prep.); in some scientific terms, < NL, L ob-]

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ob-,

prefix.

1. against; in the way; opposing; hindering, as in obstruct.

2. inversely; contrary to the usual position, as in oblate.

3. toward; to, as in obvert.

4. on; over, as in obscure. Also: o- before m; oc- before c; of- before f; op- before p; os- in some cases before c and t.

╂[< Latin ob-, related to ob against]

ob.,

1. he, she, or it died (Latin, obiit).

2. in passing; incidentally (Latin, obiter).

3. oboe.

OB (no periods),

1. obstetrics.

2. off-Broadway.

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prefix

1) denoting exposure or openness

obverse

■ expressing meeting or facing

observe

2) denoting opposition, hostility, or resistance

obstacle

■ denoting hindrance, blocking, or concealment

obliterate | obviate

3) denoting extensiveness, finality, or completeness

obdurate | obsolete

4) (in modern technical words) inversely; in a direction or manner contrary to the usual

obconical

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Origin:

from Latin ob ‘toward, against, in the way of’

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Usage

Ob- occurs mainly in words of Latin origin. It is also found assimilated in the following forms: oc- before c; of- before f; op- before p

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ob-, prefix

The Lat. prep. ob ‘in the direction of, towards, against, in the way of, in front of, in view of, on account of’. In combination with vbs. and their derivatives, the b is assimilated to certain consonants, becoming oc- before c-, of- before f-, op- before p-, and app. o- before m- (in omittĕre). In combination it has the following senses: a. In the direction of, towards; facing, in front of; as obvertĕre to turn towards, obœdīre to listen to. b. Against, in opposition, as occurrĕre to run against, oppōnĕre to place against; often merely implying the injurious or objectionable character of an action. c. Upon or over; down upon, down; as obdūcĕre to draw upon or over, obligāre to bind down, occidĕre to fall down. d. Completely; sometimes pleonastic, as obdulcāre to sweeten (completely), obdūrāre to harden greatly; often with a colouring of sense a.

In English use, ob- (oc-, of-, op-, o-) occurs.

1. In combinations already formed in Latin in the senses above-mentioned; rarely in words formed in Eng. itself on Latin elements; e.g. a. obedience, obversion; b. object, occur, opponent, opposite; c. obduce, occident; d. obdulcorate, obdurate.

2. In mod. scientific Latin, and hence in Eng., in Botany, etc., ob- is prefixed to adjs. in the sense ‘inversely’, or ‘in the opposite direction’; e.g. obcordātus (Linnæus), obcordate, i.e. cordate with the base or broad end presented; obovate, ovate or egg-shaped with the wider end presented; obtriangular, triangular with the apex downward. See below obclavate to obturbinate.

This is not an ancient L. use, where ob- was rarely combined with an adj., the chief example being oblongus oblong, which could hardly be in sense the model for these words. Apparently the prefix represents the ob- of the adv. obversè obversely, and is an abridged representation of that word.