The dictionary is no help. A web search links it to a home steam cleaning product on kaercher.com, but I'm not sure how. Is it a product type, or the activity of steam cleaning, or...?
ケルヒャー is a transliteration of the company name Kärcher. At least in Germany, the brand name is almost synonymous with their high-pressure cleaners. (Like Sellotape or Xerox or Velcro.)
The resulting word is actually pretty close to the original word (a German surname)
(closer than what would be possible in English, at least).
It is the name of a German company which produces and sells cleaning devices.
Seems to be the name of the company rather than a word itself.