। ॥ ५४८ ॥
In plain words
The sun is never actually swallowed by darkness during an eclipse - it only looks that way. But people say 'the sun has been swallowed', simply because they mistake the appearance for the fact and don't know what's really going on.
Close to the Sanskrit
Though not actually seized, the sun is called 'seized' by people, from its appearance of being seized by darkness - this is said mistakenly, from not knowing the true nature of the thing.