Additions to window over sink? Not something I can comment on perhaps

Wikipedia Word definitions in Wikipedia
A blind spot in a vehicle is an area around the vehicle that cannot be directly observed by the driver while at the controls, under existing circumstances. Blind spots exist in a wide range of vehicles: cars, trucks, motorboats, sailboats. and aircraft. ...

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Blind \Blind\, a. [AS.; akin to D., G., OS., Sw., & Dan. blind, Icel. blindr, Goth. blinds; of uncertain origin.] Destitute of the sense of seeing, either by natural defect or by deprivation; without sight. He that is strucken blind can not forget The precious ...

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
noun EXAMPLES FROM OTHER ENTRIES ▪ Critics accuse him of having a blind spot on issues of ethics. EXAMPLES FROM CORPUS ▪ He knew if some one was standing in the blind spot directly behind him, he was in trouble. ▪ It is as though the panel has developed ...

WordNet Word definitions in WordNet
n. a subject about which you are ignorant or prejudiced and fail to exercise good judgment; "golf is one of his blind spots and he's proud of it" the point where the optic nerve enters the retina; not sensitive to light [syn: optic disc , optic disk ]

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1864, "spot within one's range of vision where yet one cannot see." Of flaws in the eye, from 1872; figurative sense in use by 1907.