Prefix · direction · toward
Means "toward" or "near": adapt, advance, admit, adopt, advantage, advertise, advise.
Written by Bryan López, English teacher · Updated
Ad- comes from Latin "ad" (toward, near, in the direction of) and signals movement toward something or addition to something. It is one of the most common prefixes in English: adapt = fit toward a new use; admit = let toward the inside; advance = move toward; attract = pull toward; advise = speak toward (give direction). It generates massive numbers of Latin-based English words.
Ad- assimilates to the consonant that follows it, producing up to twelve forms: ac- (accept, access), af- (affect, afford), ag- (aggress, aggravate), al- (allow, allocate), an- (announce, annoy), ap- (appear, apply), ar- (arrive, arrange), as- (assist, associate), at- (attract, attend), and a- (ascend, aspire). The double consonant is the clue: affect = ad+fect, arrive = ad+rive, assist = ad+sist, attract = ad+tract.
Assimilates to the following consonant, producing many surface forms:
Pronunciation: /æd/ (stressed) or /əd/ (unstressed). The double consonant in words like affect, arrive, assist, attract is the visible sign of ad- assimilation. Spanish cognates: adapt/adaptar, admit/admitir, adopt/adoptar, advance/avanzar.
ad-/æd/ /əd/
Tap the button to hear how the prefix sounds. Each word in the table has its own audio.
When ad- precedes a consonant, the d assimilates to match it, creating a double: ad + fect → affect, ad + rive → arrive, ad + sist → assist, ad + tract → attract. Recognising this pattern explains both the meaning (always "toward something") and the spelling (the double consonant is the assimilation signal).
A trick to remember it
Ad- = toward, near. Spanish cognates: adapt/adaptar, admit/admitir, adopt/adoptar, advance/avanzar. Key insight: double consonants at the start of words (affect, arrive, assist, attract) often hide assimilated ad-. It is the same prefix, just disguised.
Exercise 1 · Form the word
Exercise 2 · Pick the right one
Which word hides assimilated ad- inside it?
The prefix ad- means "toward" or "near": adapt, advance, admit, adopt, advantage, advertise, advise. In Spanish it usually maps to ad-.
The prefix ad- is pronounced /æd/ /əd/. For example, "adapt".
"apt" becomes "adapt". It is a typical example of the ad- prefix.
un-, re-, pre-, dis-, over-, in-... every beginning you need to unlock thousands of English words at once.