(Latin: prefix; to, toward, a direction toward, addition to, near, at; and changes to: ac-, af-, ag-, al-, an-, ap-, aq-, ar-, as-, at- when ad- is combined with certain words that begin with the letters c, f, g, l, n, p, q, r, s, and t)

The Latin element ad carries the idea of "in the direction of" and combines with many Latin words and roots to make common English words.

The form ad- appears in this form before a vowel and before the consonants d, h, j, m, and v. It is simplified to a- before sc, sp and st.

Before c, f, g, l, n, p, q, r, s, and t; ad- is changed to ac-, af-, ag-, al-, an-, ap-, aq-, ar-, as-, and at-.

In other words, the d of ad usually changes into the same letter as the first letter of the following root or word when it is a consonant: ad-fix becomes affix, and ad-sign becomes assign; therefore, making a double consonant.

Another example includes: attract as with ad-tract (drawn towards); so it has a double t. On the other hand when ad- precedes a vowel, as with adapt, it is simply ad-apt, with one d. For the same reason, there is only one d in adore and adumbrate, because ad- has combined with orare and umbra each of which starts with a vowel.

So, remember: since these Latin words begin with vowels and not consonants, the d of ad does not double as shown in the previous examples.

ad captandum
To please.
ad captandum vulgus
To please the common people.

To please or to win the favor of the masses or the crowd.

The implication is that such actions may not be in the best interest of society, but are intended only to achieve popularity or political goals; such as, winning an elective office, publicizing movies, novels, sports, TV programs, or any promotion that wants the masses to be involved for their support.

ad clerum
To the clergy.

A statement made by a church leader and intended only for the clergy as opposed to a statement ad populum, "to the people".

ad eundem
To the same [degree].

Of equivalent value.

ad eundem gradum
To the same degree.

Sometimes abbreviated ad eundem, this phrase may be used to place blame or praise among parties to a deed. The fuller version has a special use when applied to academic life.

Considering gradum as an academic rank, under special circumstances a person holding a Master of Arts degree from one institution may be awarded the same degree by another institution without examination or even matriculation; such a degree being termed "M.A. ad eundem gradum".

ad eundem; ad eund.
Of equivalent value.
ad extra (Latin phrase)
Translation: "To the outer."

In an outward direction.

ad extremum (Latin phrase)
Translation: "To the extreme."
Ad finem fidelis. (Latin motto)
Translation: "Faithful to the end."
Ad finem spero. (Latin motto)
Translation: "I hope to the last."
Ad finem ultimum. (Latin motto)
Translation: "To the final end."

Said to be the motto of the Canadian Space Agency.

ad finem; ad fin. (adverb) (non comparable)
Relating to being at the end: The term ad finem; or its abbreviation, ad fin., is used at or near the end of a piece of writing.
ad gloriam
To glory; for glory.

See ad maiorem dei gloriam for more information.

ad gustum
To one's taste.

May be found in a cookbook: "Add salt ad gustum."

ad hanc vocem; a.h.c. (Latin)
Translation: "At this word."