Living things require energy which enters ecosystems as light and exits for the most part as heat. A food chain or web is a diagram that shows feeding relationships among members of a community.
In any food chain, arrows point up to the next trophic or feeding level. Therefore, arrows indicate that the food chain is progressing from one organism to the next in a feeding relationship. Look at the food chain below:
grass--> grasshopper-->frog--> snake-->hawk
The autotroph or producer is the grass, a green plant capable of capturing energy from the sun and converting it to the organic compound glucose which is chemical energy.
The grass will be eaten by a primary consumer or herbivore which is the grasshopper, a plant eater. The grasshopper will be consumed by a secondary consumer, a frog which is a carnivore. A snake can eat the frog--it is a third level consumer and a hawk can eat the snake--a fourth level consumer. It is assumed that all levels will eventually have the matter in their bodies returned to their basic elements via the action of decomposers which are bacteria and fungi and return to the environment.
For your question, when you see an arrow, it indicates the organism that the arrow is pointing to feeds on the organism BELOW it, so you'd say "feeds on."