observation

An individual number which is the core of the data: e.g. 84

dimension

Dimensions define how the observations divide up different slices of the data e.g.: by employment status, age, location and date. (The ONS generally don't consider locations or dates to be dimensions; but we treat them in a very similar manner).

dimension label

Each observation will have values associated with each dimension: the labels might be 'unemployed', 'aged 16-21', 'Little Linford' and '2010'

datamarker

A replacement or an addendum to an observation. The 84 might be replaced by a datamarker ".." to mean suppressed, or have a trailing 'p' to say that it's provisional.

The cells in the spreadsheet that represent the title of something. e.g. For a time dimension, the cells containing the years.

selector (xypath)

A method on a bag which chooses cells from a table or other bag, and returns a bag.

tab (excel)

A page in an Excel workbook.

cell (excel)

An individual item in a spreadsheet. e.g. the cell at position C3.

timeunit (ons)

The length of a time period. e.g. Quarter.

cell-function (xypath)

A function which takes a cell and returns True or False depending on the cell's contents.

direction (xypath)

UP, DOWN (and their synonyms ABOVE, BELOW) and LEFT and RIGHT.