row.names(x)
row.names(x) <- value

rownames(x, do.NULL = TRUE, prefix = "row")

rownames(x) <- value

colnames(x, do.NULL = TRUE, prefix = "col")

colnames(x) <- value

####################################
results <- data.frame(matrix(c(1,2,3,4),nrow=2,ncol=2))
rownames(results) <- c("a","b")

#####################################

> colnames(data)
[1] "col1" "col2" "col3"
>
> # set the name of column 2
> colnames(data)[2] <- ‘column 2‘
> colnames(data)
[1] "col1" "column 2" "col3"
>
> # you can assign all of the columns at once, if you wish


REF:
https://stackoverflow.com/questions/2281353/row-names-column-names-in-r

http://www.astrostatistics.psu.edu/su07/R/html/base/html/colnames.html

http://earlh.com/blog/2009/06/29/column-names-of-r-data-frames/

Get and Set Column/Row Names for Data Frames