Cherubim and seraphim are both types of angelic beings mentioned in several Abrahamic religions.
Their descriptions and characteristics vary throughout time and depending on which canon you are going by.
Here are some interesting characteristics that have been attributed to the celestial beings:
What are Seraphim?
The word seraph actually means "burning one". If that isn't fiery enough, it's thought that Lucifer originally belonged to this angelic hierarchy before he fell from grace.
In the Hebrew Bible, the word seraph is also associated with the symbol of a serpent.
The Christian Bible depicts them as six-winged angels made of fire (Book of Isaiah) and they also sit within the highest rank of angelic hierarchy.
What are Cherubs?
I find cherubs (the singular form of cherubim) quite fascinating actually. Before I go into any detail about what they are, I should probably mention what they're not.
These days, many people associate the word 'cherub' with chubby baby-faced angels, but the correct term for this artistic impression of an angel is actually a putto (or putti in the plural form).
Just like seraphs, there are varying descriptions of what cherubs look like. One depiction sees them with the face of an ox or a lion, whilst another sees them with many eyes (meant to represent their all-seeing nature).
One thing that brings all these cherub figures together is their association with God. In both artistic and Biblical canon, cherubs are the angels that accompany God or signify his presence.