Tester derives from the Old French word "teste," meaning "head" or "skull."
Meaning and Origin:
A device used to examine the eyesight:
In the 16th century, a "tester" was an instrument used in hospitals to test patients' vision by placing a candle before their eyes and observing the reflection in their pupils.
This usage is believed to stem from the fact that the instrument was originally placed on the patient's head (teste).
A canopy over a bed:
A "tester" is also a canopy or tester bed, a frame suspended over a bed to hold curtains or netting.
This usage likely originated from the practice of placing a tester on the tester bed to examine patients' vision.
Someone who tests or examines:
A "tester" can also refer to a person who conducts tests or exams, such as a food taster or a quality assurance tester.
This usage is derived from the general sense of "testing" or "examining."
A part of a garment that covers the head:
In the context of clothing, a "tester" is a short piece of fabric worn over the head, such as a kerchief or a tiara.
This usage is related to the original meaning of "teste" as "head."
Examples:
"The optometrist used a tester to examine my eyesight."
"The canopy over their bed was a beautiful tester."