абака is an Russian word started with а. Here is the definition of абака in English

noun абака (f)
abacus, frame holding bars strung with beads which are used to make mathematical calculations; uppermost part of a column (Architecture); abaca, Philippine plant which yields long fibers that are used to make rope and other items

абак, абакe, абакам, абаками, абаках, абаке, абаки, абакой, абакою, абаку