An eyelash or simply lash is one of the hairs that grows at the edge of the eyelid. It grows in three layers on the edge of the eye lids. Eyelashes protect the eye from debris, dust and small particles and perform some of the same functions as whiskers do on a cat or a mouse in the sense that they are sensitive to being touched, thus providing a warning that an object (such as an insect) is near the eye (which then closes reflexively).
The Ancient Greek word for eyelash transliterated as blepharon, which is seen as a root in biological terms like Blephara.
The eyelashes of the human embryo develop from the ectoderm between the 22nd and 26th week of pregnancy. Natural eyelashes do not grow beyond a certain length, and fall off by themselves without any need for trimming. Eyelashes take about seven to eight weeks to grow back if pulled out, but constant pulling may lead to permanent damage. Their color may differ from that of the hair, although they tend to be dark on someone with dark hair and lighter on someone with light hair. Eyelash hair is not androgenic and is therefore not affected by puberty.