My dictionary absolutely implies that, it even claims that all the sciences were split of from Philosophy and that a common modern topic of Philosophy is the theory of science. The point of Philosophy is to define truth in all aspects, how is that not science? It's even in the name: "friend of truth". Philosophy is even more fundamental and formal than mathematics. Mathematics asks what sound systems are, what properties they have and how they can be generalized. Philosophy asks, what something truly is, what it means to know, what it means to have a system and whether it's real. The common trope of going even more fundamental/abstract goes: "biology -> chemistry -> physics -> mathematics -> philosophy"