>>>>Thank you all! Yet I cannot grasp the difference completely (rather subtle for my non-English ear), but surely I'm less confused now.
>>>
>>>Just an opinion: indefinite article sounds rather wrong to me. "Use to remove a member object from a collection." sounds like you can use that method to remove any member from any collection, which is not the case.
>>
>>It is the case. The Remove() method is not tied to one instance, but exists on every instance, and can be used on any of them.
>
>But it is tied to one instance - *the* instance that invokes it.

But in the context there is no definite instance of a collection. If there were, we would know it's name or location in the code, but we don't.
"A car is faster than a Bicycle". Although this statement is true only for an object based on the type car, it defines the property for any car. The fact of the movement of the fast car is tied to the real life situation where you have "The" car driving down the road and ultimately overtaking the bicycle. However, in the context of describing the property of the car you don't speak about a specific car, it is indefinite which one actually is going to have this property you are talking about.

Any dictionary entry works the same way:
"Stove": a piece of equipment that burns fuel or uses electricity in order to heat a place

It's indefinite, although you are talking about a specific stove you may be looking at, the definition in the dictionary applies to any kind of stove. There may also be other ways to heat a place besides using a stove.

>'a' would only seem correct to me if (in .NET) there was a static method of the Collection type. e.g.:

Collection.Remove(collection,,element)

>
>
>>The use case example changes it from "a" to "the" because you fill in the blanks.
>
>
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>>Until then it is "the function to remove a member object from a collection."
>>
>>
>>> You can use it only on the members of THE collection you are mentioning, and no other.
>>>
>>>I guess the phrasing with the indefinite artcle is there just by inertia, blindly following the style used when describing functions:
>>>

SIN( ) Function  
>>>Returns the sine of an angle.