Did the Buddha teach meditation to lay people? During his lifetime, did the Buddha teach meditation to lay people, or did he teach meditation only to monks? 

Are there any references to this in the Pali Canon or commentaries?

It's clear that all Buddhists, including lay people, should gain the Right View by learning the Dhamma, for that is the first step on the Noble Eightfold Path. There are also references in the Pali Canon for lay people to live a virtuous life, for example in the Sigalovada Sutta.

However, most of the meditation teachings appear to target monks.
The Buddha taught people according to what interest them. Maybe, there were few lay people interested in meditation while still enjoying lay lifestyle then. 

Though there is no record of such meditation suttas teaching to lay people, I believe a few excellent lay disciples received meditation guidance from the Buddha. For example, there is Uttarā Nandamātā who is described as "the best of women disciples in meditative power (jhāyīnam)". There is also Citta the Householder who is well-versed in meditation. There is a whole fascinating Samyutta about him.