The term "cam" refers to the WHOLE OF the rotating piece of metal attached to a rotating shaft, NOT to any particular part of the "profile" of the cam, that defines how far some lever ("follower") gets pushed as the cam rotates.

A typical example of a "cam" is a rotating piece of metal that is pushing a "rod" commanding the opening or the closure of an input or output valve of an internal combustion engine.

In this picture you can see two "cams" in front of the sprocket:




A "cam" is the WHOLE OF a "rotating profile"; here is a "cam" - it's the WHOLE of the rotating piece with a specific profile:



Not all "cams" have a simple profile with just one "crest" (брегаста осовина са само једним брегом) - the profile of a cam can be quite complex. Got no time to lock for a picture of some complicated cam right now.

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Note added at 13 hrs (2021-08-09 00:02:46 GMT)
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another example of a "cam" - a rotating piece of metal that is not a simple circle:

the climbing cam



the 4 "cams" are the green bits on the top

https://www.climbing.com/gear/2012-gear-guide-how-to-buy-cam...

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Note added at 13 hrs (2021-08-09 00:15:21 GMT)
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some more complex shapes:




https://technologystudent.com/cams/cam2.htm


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Note added at 13 hrs (2021-08-09 00:24:33 GMT)
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https://performancetrends.com/Definitions/Cam-Profile.htm



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Note added at 14 hrs (2021-08-09 00:58:12 GMT)
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in the same Wikipedia article:

A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion.[1][2] It is often a part of a rotating wheel (e.g. an eccentric wheel) or shaft (e.g. a cylinder with an irregular shape) that strikes a lever at one or more points on its circular path. The cam can be a simple tooth, as is used to deliver pulses of power to a steam hammer, for example, or an eccentric disc or other shape that produces a smooth reciprocating (back and forth) motion in the follower, which is a lever making contact with the cam. A cam timer is similar, and were widely used for electric machine control (an electromechanical timer in a washing machine being a common example) before the advent of inexpensive electronics, microcontrollers, integrated circuits, programmable logic controllers and digital control.

...
Disc or plate cam
The most commonly used cam is the cam plate (also known as disc cam or radial cam[6]) which is cut out of a piece of flat metal or plate.[7] Here, the follower moves in a plane perpendicular to the axis of rotation of the camshaft.[8] Several key terms are relevant in such a construction of plate cams: base circle, prime circle (with radius equal to the sum of the follower radius and the base circle radius), pitch curve which is the radial curve traced out by applying the radial displacements away from the prime circle across all angles, and the lobe separation angle (LSA - the angle between two adjacent intake and exhaust cam lobes).

The base circle is the smallest circle that can be drawn to the cam profile.

A once common, but now outdated, application of this type of cam was automatic machine tool programming cams. Each tool movement or operation was controlled directly by one or more cams. Instructions for producing programming cams and cam generation data for the most common makes of machine, were included in engineering references well into the modern CNC era.[9]

This type of cam is used in many simple electromechanical appliances controllers, such as dishwashers and clothes washing machines, to actuate mechanical switches that control the various parts.


Motorcycle transmission showing cylindrical cam with three followers. Each follower controls the position of a shift fork.
Cylindrical cam

Constant lead barrel cam in an American Pacemaker lathe. This cam is used to provide a repeatable cross slide setting when threading with a single-point tool.

A cylindrical cam or barrel cam is a cam in which the follower rides on the surface of a cylinder. In the most common type, the follower rides in a groove cut into the surface of a cylinder. These cams are principally used to convert rotational motion to linear motion parallel to the rotational axis of the cylinder. A cylinder may have several grooves cut into the surface and drive several followers. Cylindrical cams can provide motions that involve more than a single rotation of the cylinder and generally provide positive positioning, removing the need for a spring or other provision to keep the follower in contact with the control surface.
etc


as far as I can decipher this text, the "cam" is THE WHOLE OF this rotating control mechanism, and the cam lobes are the "crests" on he cam's profile.



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Note added at 14 hrs (2021-08-09 00:58:49 GMT)
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... on the cam's profile.