Difference between CNAME and SUBDOMAIN

A CNAME is a type of DNS record, where a hostname points at another hostname.

An A record is another type of DNS record, where a hostname points at an IP address.

A subdomain is what you described as 'the left side of the domain', e.g. webmasters.stackexchange.com is a subdomain of stackexchange.com. The DNS setup for a subdomain could use either an A record or a CNAME.

Your question:

Can I point both of these IPs to the same A record, with perhaps a different cname or subdomain?

doesn't really make sense. You don't point IPs at A records, you point hostnames at IPs using A records. If you're asking if you could point a domain and a subdomain at the same IP, the answer is yes.

This might be clearer with a real world example:

webmasters.stackexchange.com has an A record that points to the IP 198.252.206.140. stackexchange.com also has an A record that points to the IP 198.252.206.140.

It would therefore be possible to change webmasters.stackexchange.com to CNAME to stackexchange.com, and everything would continue to work as it does now.

(In practice, CNAMES are slightly slower than A records as they might result in an additional DNS lookup, so that's one reason why A records are more commonly used.)