Invented brand name, suitable for a range of applications.
The word "killy" contains only five letters and only two syllables. Two syllable names make popular global brands. Established brands using two syllable names include Gillette, Sony and Visa.
Killy.com is a dot-com domain. Dot com domains are the most valuable domain extension in the world, famously used by websites like twitter.com. A dot-com is the first thing people think of when they think of a website.