The word crap (meaning excrement) predates Thomas Crapper’s toilet contributions by about 2 decades.
Let’s first dispense with the myth that Thomas Crapper invented the toilet. He didn’t. The earliest toilet’s date as far back as 4th century BC in Mesopotamia. He didn’t invent the flush toilet either. That was invented in 1596 by Sir John Harington.
Thomas Crapper did patent the u-bend and the floating ballcock, which are important features of modern flush toilets.
He was a humble journeyman plumber who started his own London-based plumbing business in 1861 and became a shrewd businessman and marketer, popularizing the flush toilet, indoor plumbing, and bathroom fixtures.
What about the word crap?
It is commonly believed that the word crap is associated with Thomas Crapper. In fact, there is a specific theory that WW1 servicemen started using the word because of its appearance on cisterns bearing the Crapper name.
The word ‘crap’ is actually of Middle English origin and predates its application to bodily waste.
Its most likely etymological origin is a combination of two older words, the Dutch krappen: to pluck off, cut off, or separate; and the Old French crappe: siftings, waste or rejected matter (from the medieval Latin crappa, chaff).
It seems that the first use of the word in reference to defecating was as early as 1840 – a couple of decades before Crapper founded his plumbing company.
In the opinion of this writer, the word may have had origins prior to Crapper’s plumbing advancements, but it seems likely that its popularity and wide use might not have taken off were it not for the popular like of toilets bearing the name Crapper.
What became of Thomas Crapper & Co.?
The original business operated until 1969. It was later relaunched in 1998 and currently operates as a vintage bathroom fixtures based in Yorkshire, England. https://www.thomas-crapper.com/