Here are some modern English equivalents:
* Heaven: This is the most common and direct translation, referring to the abode of God or a spiritual realm.
* Sky: This refers to the atmosphere and the vast expanse above us, which is a more literal translation of "Heofonum".
* The heavens: This phrase is often used in a poetic or religious context, signifying the sky or the celestial realm.
The specific meaning will depend on the context in which "Heofonum" is used.