  We present pulse width measurements for a sample of radio pulsars observed
with the MeerKAT telescope as part of the Thousand-Pulsar-Array (TPA) programme
in the MeerTime project. For a centre frequency of 1284 MHz, we obtain 762
$W_{10}$ measurements across the total bandwidth of 775 MHz, where $W_{10}$ is
the width at the 10% level of the pulse peak. We also measure about 400
$W_{10}$ values in each of the four or eight frequency sub-bands. Assuming, the
width is a function of the rotation period P, this relationship can be
described with a power law with power law index $\mu=-0.29\pm 0.03$. However,
using orthogonal distance regression, we determine a steeper power law with
$\mu=-0.63\pm 0.06$. A density plot of the period-width data reveals such a fit
to align well with the contours of highest density. Building on a previous
population synthesis model, we obtain population-based estimates of the
obliquity of the magnetic axis with respect to the rotation axis for our
pulsars. Investigating the width changes over frequency, we unambiguously
identify a group of pulsars that have width broadening at higher frequencies.
The measured width changes show a monotonic behaviour with frequency for the
whole TPA pulsar population, whether the pulses are becoming narrower or
broader with increasing frequency. We exclude a sensitivity bias, scattering
and noticeable differences in the pulse component numbers as explanations for
these width changes, and attempt an explanation using a qualitative model of
five contributing Gaussian pulse components with flux density spectra that
depend on their rotational phase.
