Nuclear magnetic resonance (NMR, ¹HNMR) is an analysis tool in chemistry that is used to determine the structure and composition of organic compounds.
We measure relative to tetramethylsilane (TMS), which is set to 0 ppm.
HNMR graphs are fairly complex. Some easy to identify patterns are the following. Singlets have 0 protons on adjacent atoms, and so on.