History of the names :

A scallion, also commonly known as green onion or spring onion, is associated with various members of the genus Allium that lack a fully-developed bulb. They tend to be milder tasting than other onions and are typically steamed and set in salads in western cookery and cooked in many Asiatic recipes. Diced scallions are often used in soup, noodle, seafood, and sauce in eastern dishes. After removing the bottom half-inch or so of the root end, both the white bottoms and the green tops are commonly used.

The species most commonly associated with the name is the Welsh onion,[which means not Welsh but 'welsche' which in turn means foreign ] Allium fistulosum. "Scallion" is sometimes used for Allium ascalonicum, better known as the shallot.

The words scallion and shallot are related and can be traced back to the Greek askolonion as described by the Greek writer Theophrastus;

this name, in turn, seems to originate from the Philistine town of Ascalon (modern-day Ashkelon in Israel).

The shallots themselves apparently came from farther east.

Scallions are also sometimes known as green onions in the United States and Canada.

In Great Britain and some Commonwealth countries, scallions are called spring onions.

In Wales, they may also be referred to as gibbons.

In parts of Australia they are known as either eschallots, shallots, or spring onions depending on the region.

In parts of Scotland, they may be referred to as cibies or syboes.

In Ireland the term scallions is used.

In Catalonia there is a variety known as Calçot.

Indians call them "spring onion" and they are available widely.

 Escallion
The escallion [ pronounced scallion with its silent e) is a culinary herb.

 
Grown in Jamaica and Trinidad & Tobago, it is similar in appearance to the scallion,Welsh onion and leek, though said by Jamaicans to be more flavoursome.
Like these others, it is a (relatively) mild onion that does not form a large bulb.

The Jamaican name is probably a variant of scallion, although like scallion, this term is itself used loosely at different times to denote the spring onion, the leek, the shallot and the green stalk of the immature garden onion (Allium cepa).

The spelling escalion is recorded in the eighteenth century; scallion is older, dating from at least the fourteenth century.

To add to the confusion, the spring onion is known in some countries as the eschallot. However, the OED's reference to escalions in Phillip H. Gosse's Birds of Jamaica (1847) implies that Gosse knew the shallot and the escalion to be different herbs, and this article accepts that authority.[3] The term escallion is now not current in English outside its Jamaican usage.

Escallion is a common and much prized ingredient in authentic Jamaican cuisine, in combination with thyme, scotch bonnet pepper, garlic, pimento and allspice.
Recipes calling for escallion sometimes suggest the use of leek as a substitute, though in salads, scallions would be more appropriate; neither is seen by Jamaicans as truly adequate.
Jamaican dried spice mixtures that include escallion are available commercially.

Fresh escallion is difficult to find and expensive outside Jamaica itself.

In Trinidad & Tobago this herb is commonly known as 'chive' with the 'ch' pronounced as 's'.

are you confused . ?