Gravel /ËÉ¡rÃ¦vÉl/ is a loose aggregation of rock fragments. Gravel is classified by particle size range and includes size classes from granule- to boulder-sized fragments. In the Udden-Wentworth scale gravel is categorized into granular gravel (2 to 4 mm or 0.079 to 0.157 in) and pebble gravel (4 to 64 mm or 0.2 to 2.5 in).
OD - This is shorthand for oculus dextraous which means Right Eye. OS - This is shorthand for oculus sinister which really means Left Eye. OU - This is shorthand for oculus uterque which really means Both Eyes. If you see this, you'll want to enter the prescription the same on both eyes. Sphere or Power - SPH or PWR - This is the main strength of your eyeglass prescription, and is written in 0.25 increments. If the field has 'SPH', 'PL', 'PLANO', or '00', this means your there is a 0.00 power as should be entered as so.
on-screen display (OSD) An on-screen display (OSD) is a control panel on a computer monitor or television screen that allows you to select viewing options and/or adjust components of the display, such as brightness, contrast, and horizontal and vertical positioning.