A dark vertical line, running up the abdomen from the pubis to the navel (though it sometimes runs further, to the top of the abdomen) that forms during pregnancy.

(anatomy) A fibrous structure that runs down the midline of the abdomen in humans and other vertebrates.

(aerology, aerography, planetology) An ephemeral dark linear feature found on slopes that recurs seasonally.

plural of lineactant

A form of surfactant that accumulates at the two-dimensional boundaries between three immiscible phases

Able to be lined.