Definition of ad- in English:
ad-
prefix
1Denoting motion or direction to.
‘advance’- ‘adduce’
- 1.1Reduction or change into.‘adapt’
- ‘adulterate’
- 1.2Addition, increase, or intensification.‘adjunct’
- ‘adhere’
- ‘admixture’
Usage
The prefix ad- is also found assimilated in the following forms: a- before sc, sp (ascend, aspire); ac- before c, q (accede, acquire); af- before f (affiliate); ag- before g (aggregate); al- before l (allude); an- before n (annex); ap- before p (appall); ar- before r (arrest); as- before s (assume); at- before t (attend)
Origin
From Latin ad ‘to’; in the 16th century the use of ad- and its variants was extended to replace a- from a different origin such as Latin ab- (e.g. advance, from French avancer based on late Latin abante ‘in front’).
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