tab

The root tab- comes from Latin tabula, which meant a flat board or plank — the kind of smooth wooden surface a Roman would write on, lay things out on, or stand a sign upon. From this single concrete object, the whole family fans out, and the trick to remembering it is to keep that flat board in mind.

First, the board you write on. A small writing board was a tabula; in English that became tablet — at first an inscribed slab of stone or wax (the Ten Commandments on stone tablets), then a small flat shape generally. That is why a pill is a tablet (a small flat disc) and why a flat touchscreen computer is a tablet too. The shape stayed flat; only the material changed.

Second, the board you arrange things on. If you lay information out neatly in rows and columns on a flat surface, you get a table — a data table. From there, Latin tabulāre ('to set out in tables') gives English tabulate, to arrange figures into rows and columns. The everyday furniture sense of table (the thing you eat at) is the same word: a flat top on legs.

Third, the board as a flat expanse. Apply 'flat surface' to geography and you get tableland — a broad, flat, raised stretch of ground, a plateau. It is land shaped like a tabletop.

Finally, compounds: time + table -> timetable, a table that lays out times in rows. Notice the pattern across the whole family: whether it is a pill, a screen, a spreadsheet, a plateau, or a train schedule, the common thread is a flat, organized surface. Latin tabula sits quietly underneath all of them.