What is the value of cex signifies in biplot function during PCA in R



I am studying about PCA and in which I have studied that using biplot function we can plot both vector and points same graph which help us analyzing the PCA but in biplot I have read about cex argument but I am not able to understand it what it does.

my.wines <- read.csv(“http://steviep42.bitbucket.org/YOUTUBE.DIR/wines.csv”, header=TRUE)
my.prc <- prcomp(my.wines[,-1], center=TRUE, scale=TRUE)
biplot(my.prc, cex=c(1, 0.7))


cex is the number indicating the amount by which plotting text and
symbols should be scaled relative to the default. 1=default, 1.5 is 50%
larger, 0.5 is 50% smaller, etc.
In the case of the biplot, the labels can be of different sizes for the two sets by
supplying a vector of length two.

Thus the labels of the first plot will use cex = 1 and for the second will use cex=0.7

Hope this helps!