That would refer to headlights as in Murphs double headlight. If it refereed to other lights a lot of folks would be in trouble, but they are not. They wouldn't be able to pass their vehicle inspection once a year.
Here is some additional info:
Texas State Statute 547-330
Sec. 547.330. AUXILIARY DRIVING LAMPS PERMITTED. (a) A motor vehicle may be equipped with no more than two auxiliary driving lamps.
(b) An auxiliary driving lamp shall be mounted on the front of the vehicle at a height from 16 to 42 inches.
(c) Auxiliary driving lamps may be used with headlamps as specified by Section 547.333.
Sec. 547.333. MULTIPLE-BEAM LIGHTING EQUIPMENT REQUIRED. (a) Unless provided otherwise, a headlamp, auxiliary driving lamp, auxiliary passing lamp, or combination of those lamps mounted on a motor vehicle, other than a motorcycle or motor-driven cycle:
(1) shall be arranged so that the operator can select at will between distributions of light projected at different elevations; and
(2) may be arranged so that the operator can select the distribution automatically.
(b) A lamp identified by Subsection (a) shall produce:
(1) an uppermost distribution of light or composite beam that is aimed and emits light sufficient to reveal a person or vehicle at a distance of at least 450 feet ahead during all conditions of loading; and
(2) a lowermost distribution of light or composite beam that:
(A) is aimed and emits light sufficient to reveal a person or vehicle at a distance of at least 150 feet ahead; and
(B) is aimed so that no part of the high-intensity portion of the beam on a vehicle that is operated on a straight, level road under any condition of loading projects into the eyes of an approaching vehicle operator.
(c) A person who operates a vehicle on a roadway or shoulder shall select a distribution of light or composite beam that is aimed and emits light sufficient to reveal a person or vehicle at a safe distance ahead of the vehicle, except that:
(1) an operator approaching an oncoming vehicle within 500 feet shall select:
(A) the lowermost distribution of light or composite beam, regardless of road contour or condition of loading; or
(B) a distribution aimed so that no part of the high-intensity portion of the lamp projects into the eyes of an approaching vehicle operator; and
(2) an operator approaching a vehicle from the rear within 300 feet may not select the uppermost distribution of light.
(d) A motor vehicle of a model year of 1948 or later, other than a motorcycle or motor-driven cycle, that has multiple-beam lighting equipment shall be equipped with a beam indicator that is:
(1) designed and located so that the lighted indicator is visible without glare to the vehicle operator; and
(2) lighted only when the uppermost distribution of light is in use.