Definition#5
from"Google offers better-tested Chrome version"

1. Google Chrome
Google Chrome is a browser that combines a minimal design with sophisticated technology to make the web faster, safer, and easier.
In Google Chrome, you can get anywhere on the Web with one box. The address bar that sits at the top of the normal Google Chrome window simplifies your Internet experience by doubling as a search box. You can also use it to bookmark websites and stay aware about the security of a website.

2. V8 engine
V8 is Google's open source JavaScript engine.
V8 is written in C++ and is used in Google Chrome, the open source browser from Google.
V8 implements ECMAScript as specified in ECMA-262, 3rd edition, and runs on Windows XP and Vista, Mac OS X 10.5 (Leopard), and Linux systems that use IA-32 or ARM processors.
V8 can run standalone, or can be embedded into any C++ application.

3. Beta version
A 'beta version' is the first version released outside the organization or community that develops the software, for the purpose of evaluation or real-world black/grey-box testing. The process of delivering a beta version to the users is called beta release. Beta level software generally includes all features, but may also include known issues and bugs of a less serious variety.

4. Beta
'Beta' is a nickname for software which has passed the alpha testing stage of development and has been released to users for software testing before its official release. Beta testing allows the software to undergo usability testing with users who provide feedback, so that any malfunctions these users find in the software can be reported to the developers and fixed. Beta software can be unstable and could cause crashes or data loss.

5. SunSpider
A benchmark suite that aims to measure JavaScript performance on tasks that are relevant to the current and near future use of JavaScript in the real world, such as screen drawing, encryption and text manipulation. The suite further attempts to be balanced and statistically sound. It was released by Apple's WebKit team in December 2007. It was well-received, and other browser developers also use it to compare the JavaScript performance of different browsers.