aglo

Aglo is a short word with a long shadow, and the shadow is the problem. Three Esperanto words begin with the same two letters and none of them is related to this one. Agi is to act, from Latin agere. Agrabla is pleasant, from French agréable. Aglo is a bird, from Latin aquila. There is no ag- root doing duty across the three, and no -lo suffix on the end of this one: the root is agl-, entire, and the -o is the ordinary noun ending.

That matters because Esperanto rewards taking words apart, and this is one of the places where the habit misfires. The test the affixes article gives is the one to use here: strip the piece you think you have found and check that what is left is a root you actually know. Take -lo off aglo and you get ag, which is not a word, so there was no seam.

What the root does support is the regular family: aglido an eaglet with the -id- suffix for offspring, aglonesto an eyrie, and agla as an adjective for the aquiline nose and the aquiline stare. The bird carries the same symbolism in Esperanto that it does everywhere else - height, sharp sight and empire - which makes it a reliable image in poetry and a rather overused one in national coats of arms.