Origin of dig

1
1275–1325; Middle English diggen, perhaps representing an OE derivative of dīc ditch; Middle French diguer to dig (< Middle Dutch) is attested later and apparently not the immediate source

British Dictionary definitions for dig in (1 of 3)

dig in

verb (adverb)

military to create (a defensive position) by digging foxholes, trenches, etc
informal to entrench (oneself) firmly
(intr) informal to defend or maintain a position firmly, as in an argument
(intr) informal to begin vigorously to eat don't wait, just dig in
dig one's heels in informal to refuse stubbornly to move or be persuaded

British Dictionary definitions for dig in (2 of 3)

Dig
/ (dɪɡ) /

noun

NZ informal short for Digger (def. 1)

British Dictionary definitions for dig in (3 of 3)

dig
/ (dɪɡ) /

verb digs, digging or dug

noun

See also dig in, digs

Word Origin for dig

C13 diggen, of uncertain origin

Idioms and Phrases with dig in

dig in

1

Excavate trenches to defend oneself in battle and hold one's position, as in The battalion dug in and held on. This usage gained currency in the trench warfare of World War I. [Mid-1800s]

2

Also, dig in one's heels. Adopt a firm position, be obstinate and unyielding. For example, Arthur refused to argue the point and simply dug in, or The dog dug in its heels and refused to move. [Colloquial; late 1800s]

3

Begin to work intensively, as in If we all dig in it'll be done before dark. [Colloquial; second half of 1800s]

4

Also, dig into. Begin to eat heartily, as in Even before all the food was on the table they began to dig in, or When the bell rang, the kids all dug into their lunches. [Colloquial; early 1900s]