Plot Annotation

This function can be used to add labels to a plot. Its first four principal arguments can also be used as arguments in most high-level plotting functions. They must be of type character or expression. In the latter case, quite a bit of mathematical notation is available such as sub- and superscripts, greek letters, fractions, etc: see plotmath

title(main = NULL, sub = NULL, xlab = NULL, ylab = NULL,
      line = NA, outer = FALSE, …)

The main title (on top) using font, size (character expansion) and color par(c("font.main", "cex.main", "col.main")).


Sub-title (at bottom) using font, size and color par(c("font.sub", "cex.sub", "col.sub")).


X axis label using font, size and color par(c("font.lab", "cex.lab", "col.lab")).


Y axis label, same font attributes as xlab.


specifying a value for line overrides the default placement of labels, and places them this many lines outwards from the plot edge.


a logical value. If TRUE, the titles are placed in the outer margins of the plot.

further graphical parameters from par. Use e.g., col.main or cex.sub instead of just col or cex. adj controls the justification of the titles. xpd can be used to set the clipping region: this defaults to the figure region unless outer = TRUE, otherwise the device region and can only be increased. mgp controls the default placing of the axis titles.


The labels passed to title can be character strings or language objects (names, calls or expressions), or a list containing the string to be plotted, and a selection of the optional modifying graphical parameters cex=, col= and font=. Other objects will be coerced by as.graphicsAnnot.

The position of main defaults to being vertically centered in (outer) margin 3 and justified horizontally according to par("adj") on the plot region (device region for outer = TRUE).

The positions of xlab, ylab and sub are line (default for xlab and ylab being par("mgp")[1] and increased by 1 for sub) lines (of height par("mex")) into the appropriate margin, justified in the text direction according to par("adj") on the plot/device region.


Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

mtext, text; plotmath for details on mathematical annotation.

  • title
library(graphics) plot(cars, main = "") # here, could use main directly title(main = "Stopping Distance versus Speed") plot(cars, main = "") title(main = list("Stopping Distance versus Speed", cex = 1.5, col = "red", font = 3)) ## Specifying "..." : plot(1, col.axis = "sky blue", col.lab = "thistle") title("Main Title", sub = "sub title", cex.main = 2, font.main= 4, col.main= "blue", cex.sub = 0.75, font.sub = 3, col.sub = "red") x <- seq(-4, 4, len = 101) y <- cbind(sin(x), cos(x)) matplot(x, y, type = "l", xaxt = "n", main = expression(paste(plain(sin) * phi, " and ", plain(cos) * phi)), ylab = expression("sin" * phi, "cos" * phi), # only 1st is taken xlab = expression(paste("Phase Angle ", phi)), col.main = "blue") axis(1, at = c(-pi, -pi/2, 0, pi/2, pi), labels = expression(-pi, -pi/2, 0, pi/2, pi)) abline(h = 0, v = pi/2 * c(-1,1), lty = 2, lwd = .1, col = "gray70")
Documentation reproduced from package graphics, version 3.4.0, License: Part of R 3.4.0

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