'Tabular' describes information that has been set out in a table — that is, in rows going across and columns going down, so the reader can look along a line or down a line and compare. If a report gives you the numbers in tabular form, it means the numbers are in a table, not written out in sentences and not drawn as a picture.

You meet it almost always in one fixed phrase: 'in tabular form'. Reports, school papers, computer manuals, science writing. It is a formal word; in everyday talk people just say 'in a table' or 'as a table', and that is perfectly good English. If a student writes 'the results are shown in a table', nothing is lost.

It has a second life in science, where it describes a shape: a crystal or a rock formation that is flat and slab-like — thin in one direction, wide in the other two — is called tabular. Geologists say 'tabular crystals'. This is the older, more picture-like meaning: shaped like a board.

Note that the word does not mean the table you eat at, even though both words go back to the same Latin 'tabula'. That Latin word meant a flat board or plank, and English split it two ways: the furniture you put things on, and the chart with rows and columns.