What's the difference between Single and Multi-Core scores in Benchmarks?

[AMKhatri]

What's the difference between Single and Multi-Core scores in Benchmarks

Hello.
I was watching a comparison between the Samsung Galaxy Note 4 and the Nexus 6.

A benchmark was run using Geekbench 3 which revealed the following score:

Nexus 6:
Single core: 1094
Multi-Core: 3304

Galaxy Note 4:
Single core: 1041
Multi-Core: 3246

Please explain what these mean, and which would be better.

I'm looking forward to buying one of these, and I'm still confused which one would be better for me... I want the one that would last at least 5 years with "Zero Lag" etc...

I currently have the Galaxy Nexus with KitKat 4.4.4

Please advise.