from The Century Dictionary.
- noun A plate of heavy glass set in a hinged frame and fitted to a port in a ship's side.
Sorry, no etymologies found.
Now, good-bye old chap, and good-bye to the port-light too.
Some of the shadows were darker than others, because the cave ended, far-off, on a port-light, a small square of day framed in black.
He led me clean through the port-light of his cave, and down a length of steps outside to his yard on the foreshore of the Thames, where, among his barges hauled up for repairs, he paused by a formless shape covered by tarpaulins.
Island tug that had fallen alongside and drifted close under the liner's flank, a short way abaft her red port-light.
"Oh, I must see that wave!" cried the captain, imprudently climbing up to look out from the port-light above him.
If anything had happened to the port-light of that ship, we could have stationed him forward in the bows with his face looming over the rail and been well within the maritime regulations -- his face had a brilliancy which even the darkness of the night could not dim; and if the other light had gone out of commission, we could have impressed the aid of the bilious Armenian lady who was sick every minute and very sick for some minutes, for she was always of a glassy green color.