Question: What is the etymology of the word *ketchup*? I've tried searching on Google without a definitive answer.

Answer: 
Supposed to be a maritime-related deal, with traders from the British East India company returning to the West from Malaysia bringing a recipe for something called kicap (pronounced: "kee-chap," with variable spellings and ingredients). Circa 17th cent. Of note is that the original was probably the same thing now available in Asian markets, called Nampla or Nuk-nam, a fermented fish sauce. 

[Supporting link here.](http://books.google.com/books?id=KXaX4tUEOOsC&pg=PA58&lpg=PA58&dq=malaysia%20keechap&source=bl&ots=fZ6kHWHac4&sig=3emKIdZngM0fr6Bb0_9PI7GrSh4&hl=en&ei=r3HITaGxEeXr0QHCg_T_Bw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBgQ6AEwAA#v=onepage&q&f=false)

Also of interest is modern-day usage of both "catsup" and "ketchup."
To supplement @The Raven's solid answer, I offer these: 

* [Etymonline](http://www.etymonline.com/index.php?term=ketchup):

> 
> **ketchup** 
>  1711, from Malay *kichap*, from Chinese (Amoy dialect) *koechiap* "brine of fish." *Catsup* (earlier *catchup*) is a failed attempt at Anglicization, still in use in U.S. Originally a fish sauce, early English recipes included among their ingredients mushrooms, walnuts, cucumbers, and oysters (Johnson, 1755, defines *catsup* as "A kind of pickle, made from mushrooms"). Modern form of the sauce began to emerge when U.S. seamen added tomatoes.
> 
> 
> 

* An [Ngram](http://ngrams.googlelabs.com/graph?content=catsup,%20ketchup&year_start=1700&year_end=2000&corpus=0&smoothing=3) of catsup (blue line)
vs. ketchup (red line).

![http://ngrams.googlelabs.com/graph?content=catsup%2C+ketchup&year_start=1700&year_end=2000&corpus=0&smoothing=3](https://i.stack.imgur.com/OVdel.png)

* And a [quote](http://books.google.com/books?id=YkkhgGoE3_cC&printsec=frontcover&dq=the%20man%20who%20ate%20everything&hl=en&src=bmrr&ei=2Y3ITZ2PI5TUgQfE6fT-BQ&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CDEQ6AEwAA#v=onepage&q=Amoy&f=false) from Jeffrey Steingarten's excellent *The Man Who Ate Everything*:

> 
> Where did ketchup get its start? The most popular theory is that the word itself defives from *kôe-chiap* or *ké-tsiap* in the Amoy dialect of China, where it meant the brine of pickled fish or shellfish. Some people prefer the Malaysian word *ketchap* (spelled *ketjap* by the Dutch), which may have come from the Chinese in the first place. In either case, sometime in the late seventeenth century, the name (and perhaps some samples and a recipe or two) arrived in England, where it first appeared in print as "catchup" in 1690 and then as "ketchup" in 1711, at least according to the *Oxford English Dictionary*. These exotic Asian names struck an evocative chord among the British, who quickly appropriated the names for their own pickled anchovies or oysters, long in popular use and probably descendants of the fishy, fermented Roman sauces, *garum* and *liquamen.*
> 
> 
>