What is meant by active and passive in the context of transistors in ICs (Gray/Hurst)?

Question

At the start of Chapter 3 in their Analysis and Design of Analog Integrated Circuits, Gray, Hurst, Meyer, and Lewis remark that

The next three chapters analyze various circuit configurations encountered in linear integrated circuits. In discrete-component circuits, the number of transistors is usually minimized. The best way to analyze such circuits is usually to regard each individual transistor as a stage and to analyze the circuit as a collection of single-transistor stages. A typical monolithic circuit, however, contains a large number of transistors that perform many functions, both passive and active.

It is this last sentence which I'm not following. In what sense is a function "active" or "passive"? Is this a colloquialism for the fact that some transistors are just there to bias etc. others, and these others "actively" do the amplification or whatever the function of interest is? I ask because it seems the use is different than that alluded to in circuits textbooks, as discussed here for example.

Answer 1

A MOS transistor (a PMOS, generally) can be used as an on-chip weak pull-up (This is quite a common approach that can be seen in today's MCUs). So the transistor here is used as a passive device.

An NMOS with gate and source shorted together can be used as an ESD protection diode which is a passive device (Here, not the MOSFET itself but its body diode is actually used but those two are not considered two independent components). This also is a common method in IC design.

You can see a lot of BJTs with base and collector shorted together are used as diodes inside, for example, op-amp chips. That's another passive function ^{There are those who claim that a diode is an active device, but let's ignore it for now}.

Active functions must be the functions that the transistors are used as active devices such as switches or amplifiers.

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PS: I don't have the book, so I can't check if it's explained somewhere. But maybe you can.