What is 18th letter greek alphabet?

The 18th letter of the Greek alphabet is called "Rho" (ρ). It is the equivalent of the letter "R" in the English alphabet. Rho is also used as a symbol in various fields of study such as physics, engineering, and mathematics. In physics, it is used to denote density, while in engineering, it is used to denote resistivity or electrical resistance. Rho is also used as a mathematical symbol in statistics to denote the correlation coefficient. In Greek numerals, rho has a value of 100. The capital letter is written in a similar way to the English letter "P" but with a curly tail at the end. The lowercase letter is similar in shape but is slightly smaller.