(f)
MALSR - Medium Intensity Approach Light System with runway alignment indicator lights,

(g) LDIN - Sequenced flashing Lead-In Lights,

(h)
RAIL - Runway Alignment Indicator Lights (sequenced flashing lights which are installed only in combination with other light systems).

(i)
ODALS - Omnidirectional Approach Lighting System consists of seven omnidirectional flashing lights located in the approach area of a nonprecision runway. Five lights are located on the runway centerline extended with the first light located 300 feet from the threshold and extending at equal intervals up to 1,500 feet from the threshold. The other two lights are located, one on each side of the runway threshold at a lateral distance of 40 feet from the runway edge, or 75 feet from the runway edge when installed on a runway equipped with a Visual Approach Slope Indicator. (Refer to Order 6850.2A)

(2)
RUNWAY LIGHTS/RUNWAY EDGE LIGHTS - Lights having a prescribed angle of emission used to define the lateral limits of a runway. Runway lights are uniformly spaced at intervals of approximately 200 feet, and the intensity may be controlled or preset.

(3)
TOUCHDOWN ZONE LIGHTING - Two rows of transverse light bars located symmetrically about the runway centering normally at 100 foot intervals. The basic system extends 3000 feet along the runway.

(4)
RUNWAY CENTERLINE LIGHTING - Flush centerline lights spaced at 50 foot intervals beginning 75 feet from the landing threshold and extending to within 75 feet of the opposite end of the runway.

(5)
THRESHOLD LIGHTS - Fixed green lights arranged symmetrically left and right of the runway centerline, identifying the runway threshold.

(6)
RUNWAY END IDENTIFIER LIGHTS/REIL - Two synchronized white flashing lights one on each side of the runway threshold, which provide rapid and positive identification of the approach end of a particular runway.

(7)
VISUAL GLIDE SLOPE INDICATOR/VGSI (USAF) - Ground device that uses colored lights to define a vertical approach path during the final approach to a runway. Vegas use not less than two and not more than four colors. Color sectors are distinct and identifiable throughout the horizontal beam width at all intensity settings. Allowable colors are red, yellow, green, or white. Red is used to indicate the lowest below approach path sector. The display area for a VGSI is ten degrees either side of the extended runway centering beginning from the light or light bar farthest from the threshold and ending at a point four miles from the threshold. Vegas are aligned to provide a minimum of a one degree glide path over obstacles within the display area. Lateral guidance to the runway centering is obtained by reference to either visual cues or electronic aids.

(a)
VISUAL APPROACH SLOPE INDICATOR/VASI - This VGSI system provides vertical visual approach slope guidance to aircraft during approach to landing by radiating a directional pattern of high intensity red and white focused light beams which indicate to the pilot that he is "on path" if he sees red/white,  "above path" if white/white, and "below path" if red/red. Some airports serving large aircraft have three-bar VASI which provide two visual glide paths to the same runway. See paragraph 5-41.