ADD - To join or unite, as one thing to another, or as several particulars, so as to increase the number, augment the quantity, or enlarge the magnitude, or so as to form into one aggregate. Hence: To sum up; to put together mentally.
APE - A primate of the clade Hominoidea, generally larger than monkeys and distinguished from them by having no tail.
DAD - A father, a male parent.
PAD - A flattened mass of anything soft, to sit or lie on.
PAT - The sound of a light slap or tap with a soft flat object, especially of a footstep.
PEA - A plant, member of the legume (Fabaceae) family.
PET - An animal kept as a companion.
TAD - A small amount; a little bit.
TAP - A tapering cylindrical pin or peg used to stop the vent in a cask; a spigot.
APT - Suitable; appropriate; fit or fitted; suited.
DATA - Plural form of datum: pieces of information.
DEAD - No longer living.
PEAT - A pet, a darling; a woman.
TAPE - Flexible material in a roll with a sticky surface on one or both sides, adhesive tape.
PATE - The head, particularly the top or crown.
ADAPT - To make suitable; to make to correspond; to fit or suit; to proportion.
DATED - Marked with a date.
TAPED - Simple past tense and past participle of tape.
ADEPT - Well skilled; completely versed; thoroughly proficient.
ADAPTED - Simple past tense and past participle of adapt.