  We present a synthesis of fast radio burst (FRB) morphology (the change in
flux as a function of time and frequency) as detected in the 400-800 MHz octave
by the FRB project on the Canadian Hydrogen Intensity Mapping Experiment
(CHIME/FRB), using events from the first CHIME/FRB catalog. The catalog
consists of 61 bursts from 18 repeating sources, plus 474 one-off FRBs,
detected between 2018 July 25 and 2019 July 2. We identify four observed
archetypes of burst morphology ("simple broadband," "simple narrowband,"
"temporally complex" and "downward drifting") and describe relevant
instrumental biases that are essential for interpreting the observed
morphologies. Using the catalog properties of the FRBs, we confirm that bursts
from repeating sources, on average, have larger widths and we show, for the
first time, that bursts from repeating sources, on average, are narrower in
bandwidth. This difference could be due to a beaming or propagation effects, or
it could be intrinsic to the populations. We discuss potential implications of
these morphological differences for using FRBs as astrophysical tools.
