Keyword Analysis & Research: what does rd mean in medical field

Keyword Analysis

Keyword	CPC	PCC	Volume	Score	Length of keyword
what does rd mean in medical field	1.74	0.5	3204	72	34
what	0.49	0.4	9783	19	4
does	0.04	0.6	2726	66	4
rd	1.04	0.2	2021	8	2
mean	1.45	0.5	9568	65	4
in	1.84	0.1	6457	90	2
medical	1	0.3	5515	94	7
field	0.02	0.1	8673	27	5

Keyword	CPC	PCC	Volume	Score
what does rd mean in medical field	1.96	0.1	2808	20