the 17th letter of the Greek alphabet
"The symbol rho, which is the seventeenth letter of the Greek alphabet, often appears in ancient manuscripts to mark paragraphs."
The seventeenth letter of the Modern Greek and Classical alphabets and the nineteenth letter of Old and Ancient.
"The researcher spent hours analyzing how rho proteins regulate cell shape changes during migration."
Any of a family of GTP-binding proteins
The word comes from the name of the Ancient Greek letter rhô. It was originally used to represent a specific sound in that language's alphabet.