What's the (exact) naming scheme for Dell monitors?

Solution 1:

Since around 2010 the convention has been:

[Series][Diagonal][Year][Ratio or Resolution][Features]

E - Essential. Usually TN anti-glare panel, internal power, simple base, 3-year warranty.
P - Professional. Usually IPS anti-glare panel, internal power, height/rotate base, 3-year warranty.
S - Home & Small Office. TN, VA, or IPS panel, usually external power, slim base, 1-year warranty.
U - UltraSharp. IPS anti-glare panel, internal power, height/rotate base, 3-year warranty.
UP - UltraSharp with PremierColor. Additional colour gamut.
AW - Alienware. High-end gaming.
C - Commercial displays. Large format (>50") for conference rooms and classrooms.

Two digit diagonal viewable size rounded to the nearest inch; halves rounded up.

Ratio or Resolution - The first uppercase letter after the digits is most commonly the aspect ratio or QHD/UHD resolution

S - standard ratio (4:3 or 5:4),
no letter - computer widescreen (16:10)
H - HD widescreen (16:9)
W - Ultrawide (21:9)
D - QHD (1440p)
Q - 4K UHD (2160p)
K - 8K UHD (4320p)
The following have also been the first letter, but either on 16:10 (no letter) or discontinued models:
T - Touch
M - No HDMI (S/U-series only)
L - With HDMI (only used when the same model without HDMI exists)
N - With VGA (only used when the same model without VGA exists)

Features - The second uppercase letter after the digits can represent a large variety of features such as: