This is the 17185th most frequent Russian word.
столицами
The Russian word "столицами" means "by capitals" or "with capitals" (instrumental plural of "столица" - capital).
The word 'столицами' (capitals) is in the instrumental plural form, referring to cities being capitals.
Москва и Санкт-Петербург считаются главными столицами России.
Moscow and Saint Petersburg are considered the main capitals of Russia.
The word 'столицами' is used in the instrumental plural form, indicating the cities which are capitals of countries.
Мы путешествовали между столицами разных стран Европы.
We traveled between the capitals of different countries in Europe.
Here, 'столицами' represents capitals in the sense of historical centers.