How is the quality of Google's automatic "translation" for single words? In Google you can put in a word and it will give you the English on the right hand side with &quot;translation&quot; and explanation.
So let's take 半挂货车 for instance. It gives me back:

Semi-trailer truck
A semi-trailer truck is the combination of a tractor unit and one or more semi-trailers to carry freight. A semi-trailer attaches to the tractor with a fifth wheel hitch, with much of its weight borne by the tractor. Wikipedia

If I put in 小型客车 I get:

Minibus
A minibus, microbus, or minicoach is a passenger carrying motor vehicle that is designed to carry more people than a multi-purpose vehicle or minivan, but fewer people than a full-size bus. Wikipedia

These all seem to be Wikipedia references, I would assume they would be of better quality than Google Translate itself but this is the first time I'm seeing this function.
Any ideas as to the quality of these pulls?
Do not use google translate to translate a single word.  The translation can be adjusted by users of that service (and make some translation wrong intentionally).  And I have seen many examples of wrong (and funny) translation made using Google translate service on Chinese social media.   

An example of bad translation can be "物极必反" to "Extremely polar" (link to google translate).