have (v.)

Old English habban "to own, possess; be subject to, experience," from Proto-Germanic *habejanan (source also of Old Norse hafa, Old Saxon hebbjan, Old Frisian habba, German haben, Gothic haban "to have"), from PIE root *kap- "to grasp." Not related to Latin habere, despite similarity in form and sense; the Latin cognate is capere "seize.

Sense of "possess, have at one's disposal" (I have a book) is a shift from older languages, where the thing possessed was made the subject and the possessor took the dative case (as in Latin est mihi liber "I have a book," literally "there is to me a book"). Used as an auxiliary in Old English, too (especially to form present perfect tense); the word has taken on more functions over time; Modern English he had better would have been Old English him (dative) wære betere.

To have to for "must" (1570s) is from sense of "possess as a duty or thing to be done" (Old English). Phrase have a nice day as a salutation after a commercial transaction attested by 1970, American English. Phrase have (noun), will (verb) is from 1954, originally from comedian Bob Hope, in the form Have tux, will travel; Hope described this as typical of vaudevillians' ads in Variety, indicating a willingness and readiness to perform anywhere.

Definitions of have
have (v.)
have or possess, either in a concrete or an abstract sense;
She has $1,000 in the bank
He has got two beautiful daughters
Synonyms: have got / hold
have (v.)
have as a feature;
Synonyms: feature
have (v.)
go through (mental or physical states or experiences);
have a feeling
Synonyms: experience / receive / get
have (v.)
cause to move; cause to be in a certain position or condition;
Synonyms: get / let
have (v.)
serve oneself to, or consume regularly;
Synonyms: consume / ingest / take in / take
have (v.)
have a personal or business relationship with someone;
have a postdoc
have a lover
have an assistant
have (v.)
organize or be responsible for;
have, throw, or make a party
Synonyms: hold / throw / make / give
have (v.)
have left;
I don't have any money left
They have two more years before they retire
I have two years left
have (v.)
be confronted with;
Now we have a fine mess
What do we have here?
have (v.)
The stocks had a fast run-up
Synonyms: experience
have (v.)
suffer from; be ill with;
She has arthritis
have (v.)
cause to do; cause to act in a specified manner;
Synonyms: induce / stimulate / cause / make
have (v.)
receive willingly something given or offered;
The only girl who would have him was the miller's daughter
I won't have this dog in my house!
Synonyms: accept / take
have (v.)
get something; come into possession of;
Synonyms: receive
have (v.)
undergo (as of injuries and illnesses);
He had an insulin shock after eating three candy bars
Synonyms: suffer / sustain / get
have (v.)
achieve a point or goal;
Nicklaus had a 70
Synonyms: get / make
have (v.)
cause to be born;
My wife had twins yesterday!
Synonyms: give birth / deliver / bear / birth
have (v.)
have sex with; archaic use;
He had taken this woman when she was most vulnerable
Synonyms: take
have (v.)
have ownership or possession of;
How many cars does she have?
Synonyms: own / possess
have (n.)
a person who possesses great material wealth;
Synonyms: rich person / wealthy person