A transdeletion pyramid (also called a transaddition pyramid or word pyramid when inverted) is a logological

Logology

Logology is the study of recreational linguistics, an activity that encompasses a wide variety of word games and wordplay emphasizing letter patterns...

 term for the triangular representation of a list of words in which each one is a scrambled form of the above word without one letter.

This seventeen-letter transdeletion pyramid, made of inferred words in an Unabridged Merriam-Webster

Merriam-Webster

Merriam–Webster, which was originally the G. & C. Merriam Company of Springfield, Massachusetts, is an American company that publishes reference books, especially dictionaries that are descendants of Noah Webster’s An American Dictionary of the English Language .Merriam-Webster Inc. has been a...

 dictionary, can be found in Ross Eckler's

A. Ross Eckler, Jr.

Albert Ross Eckler, Jr. is a logologist and statistician, the son of statistician A. Ross Eckler. He received a B.A. from Swarthmore College and a Ph.D. in mathematics from Princeton University....

book Making the Alphabet Dance:

A N T I C E R E M O N I A L I S T
N O N M A T E R I A L I T I E S
O R N A M E N T A L I T I E S
I N T E R L A M I N A T E S
M A T E R N A L I T I E S
M A T R I L I N E A T E
T R I L A M I N A T E
T E R M I N A L I A
L A T I M E R I A
M A T E R I A L
T A L I E R A
R E T A I L
A L T E R
R A T E
T E A
A T
A