What is Botvinnik saying here?

I am not entirely sure what Botvinnik means by this.

“For one competition three or four opening systems for white and the same for black are quite sufficient. [...] But it is also very unsatisfactory for a master to play only one opening; his opponents will be well prepared for play against him, and above all his chess horizon will be too narrow, and in many positions he will simply play by rote.” (Botvinnik, Mikhail. One Hundred Selected Games. New York: Dover Publications, 2017. Print)

It is not obvious to me what Botvinnik means by ‘systems’. Generally in chess now, a system refers to a specific opening setup that can be played against almost anything. For example, King’s Indian Attack, Hippopotamus System et cetera. Knowing this would say the Dutch Defence: Leningrad, count as a separate system from the Dutch Defence: Classical, Stonewall Variation? Or does Botvinnik classify these as the same system for example, Dutch Defence. In other words, when Botvinnik refers to systems does he refer to what we would regard as openings; as in Dutch Dutch, Queen’s Gambit, or the Sicilian Defence?

Thanks in advance.

perhaps he just means "openings"