of

Multiple Entries:
  of    ob-    of-  

Concise Oxford English Dictionary © 2008 Oxford University Press:
of/əv/

▶preposition

• 1 expressing the relationship between a part and a whole.

• 2 expressing the relationship between a scale or measure and a value.

  ■ expressing an age.

• 3 indicating an association between two entities, typically one of belonging.

• 4 expressing the relationship between a direction and a point of reference.

• 5 expressing the relationship between a general category and something which belongs to such a category.

• 6 expressing the relationship between an abstract concept and a noun denoting the subject or object of the underlying verb.

• 7 indicating the relationship between a verb and an indirect object.

• 8 indicating the material constituting something.

• 9 N. Amer. expressing time in relation to the following hour.

– phrases
be of possess intrinsically or give rise to: this work is of great value.

– origin OE, of Gmc origin.

usage: It is a mistake to use of instead of have in constructions such as you should have asked. For more information, see usage at have.

Concise Oxford English Dictionary © 2008 Oxford University Press:
ob- /ɒb/ (also oc- before c; of- before f; op- before p)

▶prefix forming words of mainly Latin origin, meaning.

• 1 to, towards: obverse.

• 2 against; blocking: opponent.

  ■ concealment: occult.

• 3 finality or completeness: obsolete.

• 4 technical in a direction or manner contrary to the usual: obconical.

– origin from L. ob ‘towards, against, in the way of’.

Concise Oxford English Dictionary © 2008 Oxford University Press:
of-/ɒf/

▶prefix variant spelling of ob-. assimilated before f (as in offend).