Definify.com
Webster 1913 Edition
Certain
Cer′tain
,Adj.
 [F. 
certain
, fr. (assumed) LL. certanus
, fr. L. certus 
determined, fixed, certain, orig. p. p. of cernere 
to perceive, decide, determine; akin to Gr. [GREEK] to decide, separate, and to E. concern
, critic
, crime
, riddle 
a sieve, rinse
, v.] 1. 
Assured in mind; having no doubts; free from suspicions concerning. 
To make her 
certain 
of the sad event. Dryden.
I myself am 
certain 
of you. Wyclif.
2. 
Determined; resolved; – used with an infinitive. 
However, I with thee have fixed my lot,
Certain 
to undergo like doom. Milton.
3. 
Not to be doubted or denied; established as a fact. 
The dream is 
certain
, and the interpretation thereof sure. Dan. ii. 45.
4. 
Actually existing; sure to happen; inevitable. 
Virtue that directs our ways
Through
Through
certain 
dangers to uncertain praise. Dryden.
Death, as the Psalmist saith, is certain to all. 
Shakespeare
5. 
Unfailing; infallible. 
I have often wished that I knew as 
certain 
a remedy for any other distemper. Mead.
6. 
Fixed or stated; regular; determinate. 
The people go out and gather a 
certain 
rate every day. Ex. xvi. 4.
7. 
Not specifically named; indeterminate; indefinite; one or some; – sometimes used independenty as a noun, and meaning certain persons. 
It came to pass when he was in a 
certain 
city. Luke. v. 12.
About everything he wrote there was a 
certain 
natural grace und decorum. Macaulay.
Syn. – Bound; sure; true; undeniable; unquestionable; undoubted; plain; indubitable; indisputable; incontrovertible; unhesitating; undoubting; fixed; stated. 
 Cer′tain
,Noun.
 1. 
Certainty. 
[Obs.] 
Gower.
 2. 
A certain number or quantity. 
[Obs.] 
Chaucer.
 Cer′tain
,adv.
 Certainly. 
[Obs.] 
Milton.
 Webster 1828 Edition
Certain
CERTAIN
, a.1.
  Sure; true; undoubted; unquestionable; that cannot be denied; existing in fact and truth.The dream is certain and the interpretation sure.  Dan. 2.
2.
  Assured in mind; having no doubts; followed by of, before a noun.However I with thee have fixed my lot,
Certain to undergo like doom of death,
Consort with thee.
To make her certain of the sad event.
3.
  Unfailing; always producing the intended effect; as, we may have a certain remedy for a disease.4.
  Not doubtful or casual; really existing.Virtue that directs our ways
Through certain dangers to uncertain praise.
5.
  Stated; fixed; determinate; regular.Ye shall gather a certain rate every day.  Ex. 16.
6.
  Particular.There came a certain poor widow.  Mark 12.
In the plural number, a particular part or number; some; an indefinite part, number, or quantity.  Hanani came, he and certain men of Judah.  I mourned certain days.  Neh. 1. 2. 6.
In the latter sense, it is used as a noun; as, certain also of your own poets have said.  Acts 17.