In British English a gamp is an umbrella, and not a neat folding one. People who still use the word usually mean a large cotton canopy, often loosely tied rather than rolled tight, with a faintly comic air of bulk. The term is informal, dated, and rare in American English. It is also an eponym: English took the name of a fictional nurse and pinned it on the rain shield she would not put down.
A character before a common noun
Charles Dickens introduced Sarah Gamp, often called Sairey in the book, in Martin Chuzzlewit, issued in monthly parts from 1843 to 1844. She works as a monthly nurse and as a watcher of the dead, hired to sit with a corpse before the funeral and to attend women after childbirth, while presenting herself as a midwife. Dickens draws her as a stout, gin-soaked widow, voluble in Cockney, and equipped with an imaginary friend, Mrs Harris, who exists only in her conversation.
The umbrella is part of the costume. Mrs Gamp carries a large cotton one, worn to a faded green-brown except where a bright blue patch has been let into the crown. It is bulky, slightly unruly, and on stage often enough that later readers remembered the prop as clearly as the woman. Within a few years the surname began to slide off the character and attach to people and objects that resembled her.
When print caught up
Lexicographers agree on the source and disagree on the first year the common noun appears. The Oxford English Dictionary treats Gamp as a word taken from a proper name, places the earliest evidence in the 1840s, and cites 1846 in Bentley's Miscellany. It also splits the record by subject: a medical use in that decade, for a nurse of Mrs Gamp’s type, and a costume use in the 1850s, for the umbrella. Merriam-Webster dates the umbrella meaning to 1855. Several other dictionaries and word histories push a clear bulky-umbrella sense into the early or mid 1860s. Michael Quinion notes an 1864 description of a large, bulgy, loosely tied cotton umbrella. Green’s Dictionary of Slang records the monthly-nurse sense in 1864 and a straightforward umbrella example in 1866.
The scatter of dates is ordinary for a literary eponym. A famous surname can circulate as an allusion, still half a proper name, long before compilers treat it as an independent English noun. Capitalization in early citations is often unstable for the same reason.
No older stem to unpack
There is no native English root gamp- meaning rain, cloth, or shade, and no prefix or suffix that explains the form. The etymon is the character’s surname. English did not inherit the word from Old English and did not borrow it from French or Latin; speakers borrowed a name from a novel.
That path sets gamp apart from umbrella, which came into English from Italian ombrella, a diminutive related to Latin umbra, shade, and first named a sunshade. It also sets it apart from brolly, a clipped and altered form of umbrella that authorities place in university slang of the 1870s. The Dickens word reached print as a joke about a particular kind of umbrella; brolly later became the unmarked British shortening.
Homonyms in other languages are easy to confuse with this history and should be kept separate. Norwegian Bokmål and Nynorsk gamp means a workhorse or an old nag, from a different root related to a verb for twisting the body. Welsh gamp is only the soft mutation of camp. None of these is the source of the English umbrella word, and English gamp has no true cognates in the comparative sense, because it is a name, not an inherited Germanic or Romance stem.
Dickens did not need an older etymology for the surname to make the joke work. Once the nurse was famous, the object she carried was famous with her.
From woman to trade, then to the object
The first transfer was from person to profession. Readers used Gamp, often still capitalized, for a monthly nurse or a midwife of the Dickensian stamp: bulky, fond of the bottle, and none too scrupulous. That is the medical strand the OED assigns to the 1840s, and it matches how the character earned her living.
The second transfer was from person to accessory. The umbrella was the most portable emblem of the role, so gamp came to mean the thing itself, especially a large or untidy one. Later usage could treat the word as a mild rebuke. A tightly rolled umbrella was respectable; a gamp was the same object allowed to go slack, cotton showing, ribs not quite under control.
The nurse sense has largely died out. The umbrella sense lasted longer in British and some Commonwealth English, turning up in newspapers, memoirs, and crossword clues well into the twentieth century and, more rarely, after that. It never replaced umbrella as the ordinary name of the object. Gamp kept a flavour of size, age, and comedy, which is why writers could list it beside brolly and still mean something bulkier.
A lag worth remembering
If you meet the word now, you are probably reading older British prose or solving a puzzle. The concrete fact to take away is the delay in the record. Dickens put the nurse and her patched cotton umbrella on the page in 1843–44, but dictionaries still do not agree on when gamp became a common noun for the rain shield, with umbrella dates ranging from the mid-1850s to the mid-1860s. That lag is typical of names that escape a book. A character can be proverbial for years before her surname is treated as just another English word for something in the hall stand.
The origin of the word gamp is that delay made visible: a proper name that outlived its owner and settled on the one prop she refused to leave behind.