SSL
Square, Suffix and Lot: the District's parcel identifier. It is written fixed-width with the spaces kept, so the lot under 1350 Pennsylvania Avenue NW is "0255 0800" with four spaces, not one. Both the address register and the permit feed store it that way, and a trimmed version matches nothing.
Square
A city block, numbered. The first half of an SSL.
Lot
A parcel within a square, and the second half of an SSL. Lot numbers cluster rather than running in sequence: 133,936 of the roll's lots are numbered below 1000 and 82,212 sit in the 2000s, which is why one square can carry lot numbers that look unrelated. The roll publishes no column saying which kind a lot is, so this report does not label them.
Quadrant
NW, NE, SW or SE: which quarter of the city an address sits in, measured from the Capitol. Part of the address, not an annotation.
Ward
One of eight, numbered Ward 1 to Ward 8 and confirmed against the address register. Most District records carry it, and the daily lists here group by it.
ANC
Advisory Neighborhood Commission: a smaller elected body within a ward. The register writes it as the ward number and a letter, "ANC 2C", and carries a smaller unit beside it, the single member district, "SMD 2C03". ANCs are consulted on zoning and licensing in their area.
MAR
Master Address Repository: the District's official register of addresses, and what an address is checked against here. 144,422 points.
ITSPE
Integrated Tax System Public Extract: the published assessment roll, one row per tax lot, carrying value, use, land area, tax class and the prior year's assessment. 221,486 lots.
Neighborhood cluster
The District groups blocks into numbered clusters rather than using everyday neighbourhood names in its data. The permit feed carries the cluster; a name like Shaw or Petworth is not what the record says.