Use of "groin" as a verb [closed]

I came across this line when reading Owen's Strange Meeting:

It seemed that out of the battle I escaped

Down some profound dull tunnel, long since scooped

Through granites which Titanic wars had groined.

What does the last line really mean? Going by the dictionary, groin as a verb stands for 'to form the line of intersection of two vaults', but with this I am unable to bring Titanic wars into the picture.

Solution 1:

A groined surface (Wikipedia link) would technically look like this:

Owen used the architectural term poetically to describe the inexorable power and awful grandeur of the war's effects on solid granite.

In one person's analysis:

"Groined" is used here in place of the word grooved; the walls of the tunnel had been grooved by the titanic wars displacing the granite.

Solution 2:

Theres two meanings:

n1) Old French groign (French groin), Burgundian groigno, Provençal groing, grong, feminine groingna, Italian grugno, Old Portuguese gruin < popular Latin *grunnium, < Latin grunnīre to grunt like a swine

n2) originally grynde , grinde of uncertain origin; connection with grain n.2 is excluded by the early form. The form grine appears in 1530, but did not finally displace grind until the last quarter of the 16th cent., when it underwent corruption into groin , probably through phonetic association with groin n.1

Prof. Skeat suggests that the original sense may have been a channel or depression (compare 2), and that the word may be identical with Old English grynde , recorded only in the sense of ‘abyss’, but etymologically capable of meaning ‘depression’, ‘valley’ ( < prehist. *grundjo- , < *grundu- ground n.; compare German grund , used dialect for ‘valley’; also grindle n.1, grindlet n.).

The grunting one seems more like what would happen in a battle.

Upvote for the other answer though!