Yes, it looks like a mombin seed, one of my favorite fruits and trees. Called jocote in CR, they are very popular and in season right now, widely sold in markets and on the streets. The fruits are only about three or four centimeters long. Not much to eat considering such a large seed. You can find the seeds all along the CR roadsides where Ticos have chewed the soft sweet creamy flesh off and then spit the large seeds out. The trees are very fast growing and are grown from large limb cuttings, often planted as fence posts where they then grow into large trees in long rows.