Parallelogrammatic (a.)
definition: Of or pertaining to a parallelogram; parallelogrammic.

Parallelogrammatic is an 18 letter word that begins with a P and ends in a C

Parallelogrammical (a.)
definition: Having the properties of a parallelogram.

Parallelogrammical is an 18 letter word that begins with a P and ends in an L

Pepsinhydrochloric (a.)
definition: Same as Peptohydrochloric.

Pepsinhydrochloric is an 18 letter word that begins with a P and ends in a C

Phanerocrystalline (a.)
definition: Distinctly crystalline; -- used of rocks. Opposed to cryptocrystalline.

Phanerocrystalline is an 18 letter word that begins with a P and ends in an E

Photogalvanography (n.)
definition: The art or process of making photo-electrotypes.

Photogalvanography is an 18 letter word that begins with a P and ends in a Y

Physico-philosophy (n.)
definition: The philosophy of nature.

Physico-philosophy is an 18 letter word that begins with a P and ends in a Y

Pleuroperipneumony (n.)
definition: Pleuropneumonia.

Pleuroperipneumony is an 18 letter word that begins with a P and ends in a Y

Postmaster-general (n.)
definition: The chief officer of the post-office department of a government. In the United States the postmaster-general is a member of the cabinet.

Postmaster-general is an 18 letter word that begins with a P and ends in an L

Poupart's ligament
definition: A ligament
Of fascia extending in most mammals from the ventral side of the ilium to near the symphysis of the pubic bones.
Poupart's ligament is an 18 letter word that begins with a P and ends in a T

Pseudoneuropterous (a.)
definition: Of or pertaining to the Pseudoneuroptera.

Pseudoneuropterous is an 18 letter word that begins with a P and ends in an S

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