Inch

An inch was a unit of length.

The Builders resembled eight-inch slugs. (ST: Primitives)

The Life Knife was eight inches deep by three inches wide. (TW: Everything Changes)

Princess Cilia used Ulian shrinking technology to make heself six inches tall and hid on top of a Christmas tree, pretending to be an angel. (WC: The Doctor on My Shoulder)

The Vinvocci, Rossiter, was one inch taller than the Master in his "Harold Saxon" incarnation. The Tenth Doctor noted this when Rossiter was disguised as a member of the Master Race. The Master failed to notice this difference in height. Rossiter knocked him out with his rifle. (DW: The End of Time)

The hull of the Octopus Rock was made of seven inches of steel. (BBCR: Submission)

At twenty-seven years old, Janet Rae Tanner was five foot nine inches and a hundred nineteenpounds, as noted by Jack Harkness. (TW: The Middle Men)

One of the diseases created by the Viyrans was a metallic-looking worm which was six inches long. (BFA: Urgent Calls)

The typical Psychic Worm was less than an inch long. (BFA: The Wormery)

Uncle, the servant of House, having been damaged over time and repaired by the body parts of dead Time Lords, had a right arm two inches longer than the other when he died. (DW: The Doctor's Wife)