From A-z, Strange (Mostly) English Words with Many Repeated Letters

Galatasaray

Has five A’s and it is the name of a Turkish football team.

Bibble-babble

Has six B’s and all it means is babble/idle talk.

Pneumonoultramicroscopicsilicovolcanoconiosis

Has six C’s and is just a famously long word for a respiratory disease.

Dodecahemidodecahedron

Has five D’s and it is a non conconvex uniform polyhedron.

Ethylenediaminetetraacetate

Has seven E’s. The widely used abbreviation is EDTA. It is an acid, an amino acid. It is also used as a drug

Riffraff

Has four F’s and it means undesirable people, or a group of people, regarded as disreputable or worthless.

Llanfairpwllgwyngyllgogerychwyrndrobwlllantysiliogogogoch

Has seven G’s and is a famously long Welsh placename. The short name is Llanfair PG and it can be found on the island of Anglesey in Wales.

High-Churchmanship

Has five H’s and it means nothing but the state of being a High-Churchman. It is usually used as a faction of the Anglican Church.

Floccinaucinihilipilification

Has nine I’s and it means “the estimation of something as valueless.”

Jejunojejunostomy

Has four J’s and it is a surgical procedure carried out on the intestine.

Knickknack

Has four K’s and it usually means an ornamental trinket or gimcrack.

Llullaillaco

Has six L’s and it is a mountain on the Andes.

Mammogram

Has four M’s and it is a form of breast x-ray to find different types of tumors or cysts.

Nonannouncement

Has six N’s. It is very rare as we usually use no announcement and that is exactly what it means.

Pneumonoultramicroscopicsilicovolcanoconiosis

Has nine O’s and it is another respiratory disease.

Whippersnapper

Has four P’s and it is a young, impertinent person.

Albuquerque

Has two Q’s and it is a city in New Mexico.

Refrigerator

Has four R’s and as everybody knows it is an appliance to keep the food cool.

Possessionlessness

Has eight S’s and it is the state of being without possessions.

Tittle-tattle

Has six T’s. A good one here, it means gossip…

Humuhumumukunukuapua’a

Has nine U’s and it is a fish, a Hawaiian fish.

Ovoviviparous

Has three V’s and it means producing eggs that are hatched within the body, so that the young are born alive but without placental attachment, as certain reptiles or fishes.

Wow-wow

Has four W’s and it is a commonly used word and it is a type of gibbon.

Hexahydroxycyclohexane

Has three X’s and it is a chemical compound, also a part of the vitamin B complex.

Polysyndactyly

Has four Y’s and it is a webbing of the hands or feet.

Zenzizenzizenzic

Has six Z’s and it is the eighth power or exponent of a number. The term was suggested by Robert Recorde, a 16th century Welsh writer of Mathematics books.