a line burn

There is a passage in The Old Man and The Sea, “The old man would have liked to keep his hand in the salt water longer but he was afraid of another sudden lurch by the fish and he stood up and braced himself and held his hand up against the sun. But it was in the working part of his hand. He knew he would need his hands before this was over and he did not like to be cut before it started.”
Please, tell me what “a line burn” means! Is that grammatical?

It refers to an abrasion caused by fishing line passing rapidly over his hand. The line had cut into his flesh.

p.s. Yes, line burn is grammatical. It means a burn caused by a (fishing) line.

owlman5 said:

It refers to an abrasion caused by fishing line passing rapidly over his hand. The line had cut into his flesh.

p.s. Yes, line burn is grammatical. It means a burn caused by a (fishing) line.

Thank you, you help me a lot!

Note that the word "line" is used like an adjective here: it tells us what kind of burn it is. Just as an "acid burn" is a burn caused by acid, a "line burn" is a burn caused by a (fishing) line. This noun+noun combination is standard in English grammar. If we describe something as an xy, the second noun tells us in general terms what this thing is: a y (in this case, a burn), while the first noun (x) specifies what kind of y it is (in this case, the first noun is the cause of the burn - a fishing line).