[ret-i-kuh
l] 
| a network of fine lines, wires, or the like placed in the focus of the eyepiece of an optical instrument. |
| ret·i·cle (rět'ĭ-kəl) n. A grid or pattern placed in the eyepiece of an optical instrument, used to establish scale or position. [Latin rēticulum, diminutive of rēte, net.] |