Does "LED Chip" mean the LED light source in a luminaire?

No, although the term "LED chip" is often used by online retailers to denote the LED light source, in particular SMD LEDs, in a luminaire, they're not the same thing. Also called "LED die", the LED chip refers to the semiconducting p-n junction, and thereby differentiate from the term LED, which typically includes both a chip and its packaging. LED chips are unpackaged semiconductor products which are prone to performance degradation, or aging, if exposed for an extended time in an atmosphere full of humidity or chemical. Therefore, an LED chip is required to be packaged before it can be used in an application. One of the primary purposes of LED packaging is to protect the LED chip from being damaged physically or chemically to ensure the proper functionality of the chip. In the LED industry, the manufacturing process of LED chips and the packaging process of LED are independent processes. Frequently, an LED package consists of a substrate, an LED die arranged on the substrate, and an encapsulation formed on the substrate to cover the LED die.

As you can see it's an LED package that is the basic LED component in an LED luminaire. LED chips rely on a packaging structure for mechanical, electrical, thermal, and optical supports. The term "LEDs" that often appears on luminaire manufacturer's cut sheets refers to LED packages, LED arrays, LED modules, or LED light engines.