Lighting lamps and light bulbs are described by a shape, diameter, length and screw type designation. This normally is in the form of letter(s) followed by a number followed by an optional letter.
A standard 60-100 watt household bulb is an A19 A = Arbitrary Shape (see below); 19 = 19/8th in. [2 3/8 inch] in diameter [A metric A60 (60 mm in diameter) is the equivalent], with an E26 screw base.
Source: EagleLight

LED Lights

Fluorescent tube bulbs
Circular fluorescent light bulbs differ in many ways and sometimes come with manufacture-only specifics. Bulbs range from 5"-12" in diameter.

Source: GElighting.com

Sockets and base type:
'Exx', 'E' stands for 'Edison' and 'xx' refers to the diameter in millimeters as measured across the peaks of the thread on the base (male)

E10, E11, E12, E14, E17, E26 (Standard Bulb), E27, E36, E39, BA15, SC,
GU10, GU24, G4, G5.3, GY6.35, GU8 GY8, G9, G12
   
LED light bulb sockets and bases are manufactured to the same standards as
halogen, incandescent and other traditional lights.
Edison Screw-in (ES)
Candelabra: E12 (diameter of 12 mm) [0.47"]
Intermediate: E17 (diameter of 17 mm) [0.67"]
Medium or Standard: E26 (diameter of 26 mm [1.02"]
Mogul: E39 (diameter of 39 mm) [1.54"]

More at Galan.com
EnergyStar categorizes bulbs as:
Omnidirectional: A, BT, P, PS, S and T 
Decorative: B, BA, C, CA, DC, F, G
Directional: R, BR, ER, MR and PAR 

See:
 LED Light Bulb Base Types | EagleLight.com
and LED Light Bulb Base Types | gallan.cc

BR (for bulged reflector) bulbs are lamps with "wide flood" beam angles, which means that they provide more than a 45 degree angle when lighting an area.

Multi Faceted Reflector (MR) Halogen and LED

Beam Angle (spot/flood)

Code	Typical MR16	Typical PAR	Description
VNSP	<7 degree	s<15 degrees	Very narrow spot
NSP	5-15 degrees	15-30 degrees	Narrow spot
SP	16-22 degrees	30-60 degrees	Spot
NFL	23-32 degrees	60-90 degrees	Narrow flood
FL	32-45 degrees	90-120 degrees	Flood
WFL	45-60 degrees	120-160 degrees	Wide flood
VWFL	60+ degrees	>160 degrees	Very wide flood

Source: LED Beam Angle | WhichLedLight.com

Candelabra bulbs are sometimes listed as B and BA and C. Bases are typically E12.

Terms:
ACEC - Advisory Committee on Electromagnetic Compatibility (part of IEC)
ES - Edison Screw
IEC - International Electrotechnical Commission (or CEI in French) - Sets standards
MES - Medium Edison Screw