Is

Multiple Entries:
  IS    is    I    Is.    be  

Concise Oxford English Dictionary © 2008 Oxford University Press:
IS

▶abbreviation Iceland (international vehicle registration).

– origin from Icelandic Ísland.

Concise Oxford English Dictionary © 2008 Oxford University Press:
is/ɪz/

third person singular present of be.

Concise Oxford English Dictionary © 2008 Oxford University Press:
I1 (also i)

▶noun (pl. Is or I's)

• 1 the ninth letter of the alphabet.

• 2 denoting the next after H in a set of items, categories, etc.

• 3 the Roman numeral for one.

Concise Oxford English Dictionary © 2008 Oxford University Press:
I2

▶pronoun [first person sing.] used by a speaker to refer to himself or herself.

– origin OE, of Gmc origin.

usage:
It is correct to say between you and me rather than between you and I: see usage at between
On whether to say you have more than me or you have more than I, see usage at than.

Concise Oxford English Dictionary © 2008 Oxford University Press:
I3

▶abbreviation

• 1 (I.) Island(s) or Isle(s) (chiefly on maps).

• 2 Italy (international vehicle registration).

▶symbol

• 1 electric current.

• 2 the chemical element iodine.

Concise Oxford English Dictionary © 2008 Oxford University Press:
Is.

▶abbreviation

• 1 (also Isa.) Isaiah (in biblical references).

• 2 Island(s).

• 3 Isle(s).

Concise Oxford English Dictionary © 2008 Oxford University Press:
be/bi/

▶verb (sing. present am; are; is; pl. present are; 1st and 3rd sing. past was; 2nd sing. past and pl. past were; present subjunctive be; past subjunctive were; present participle being; past part. been)

• 1 (usu. there is/are) exist; be present.

• 2 take place.

  ■ occupy a position in space.

  ■ stay in the same place or condition.

  ■ come; go; visit.

• 3 (when connecting a subject and complement) having the specified state, nature, or role: Amy was 91.

  ■ represent or signify.

• 4 informal say: last time I saw her she was all ‘You need to quit smoking!’.

▶auxiliary verb

• 1 used with a present participle to form continuous tenses.

• 2 used with a past participle to form the passive voice.

• 3 used to indicate something that is due to happen.

  ■ used to express obligation or necessity.

  ■ used to hypothesize about something that might happen.

– phrases
the be-all and end-all informal a feature of an activity that is of greater importance than any other.
not be oneself not feel in one's usual physical or mental state.
-to-be of the future: his bride-to-be.

– origin OE bēon, an irregular verb whose full conjugation derives from several orig. distinct verbs; the forms am and is are rel. to L. sum and est.