Heterophonic texture is when the same melody is played and it overlaps in other voices. I'm pretty sure canons do this to, but the web did not say anything about this.
2 Answers
Heterophony is defined somewhat ambiguously, and its use depends on the music/era concerned.
In general, however, the primary characteristic of heterophony is that the voices sound the melody simultaneously but in variation from each other. "Simultaneous" here means that the same melodic moments occur at the same time.
In a canon, however, the voices sound the melody at different times. They overlap, yes, but are not simultaneous in the sense required by heterophony. Canons are polyphonic, but not heterophonic (which is itself considered a special case of heterophony).
By "canonic entries", I take you to mean that the voices enter at different times, but don't necessarily continue in canon. In that case, it seems like a matter of interpretation, depending on whether, after entering, the voices continue to elaborate the same, simultaneous melody.
Wikipedia also has a reasonable explanation.
While Aaron's answer is correct, generally speaking, it is nonetheless possible to construct a canon that is truly heterophonic, for example as a theme with variations in which the variations are melodic embellishments and successive voices begin with the theme as the preceding voice begins the first variation. For example
X:1
T:Heterophonic Canon
M:4/4
K:C
[L:1/2] c'b/a/ |ga/b/ |[L:1/8] !segno!c'e'd'c' bc'ba |gabg agab |[L:1/16] !segno!c'gab c'd'e'd' c'bac' baga |gdef gabg abc'a bc'd'b |]
Yielding
X:1
T:Heterophonic Canon
M:4/4
K:C
%%staves {(I) (II) (III)}
V: I clef=treble middle=b
V: II clef=treble middle=b
V: III clef=treble middle=b
%
[V: I][L:1/2] c'b/a/ |ga/b/ ||
[V: II][L:1/8]c'e'd'c' bc'ba |gabg agab ||
[V: III][L:1/16]c'gab c'd'e'd' c'bac' baga |gdef gabg abc'a bc'd'b ||
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@Aaron thanks. I was inspired by Pachelbel's Canon, but obviously replacing the harmonic relationships between different periods in the melody with heterophonic relationships. (And this was partly triggered by my initial misreading of the question as asking about homophonic canons rather than heterophonic.) I can imagine that an application of this technique, perhaps with a longer period and certainly with more of them, might indeed yield a super cool piece of music, but that would have to be realized by someone with a better understanding than I have of how to use heterophony effectively.– phoogSep 15, 2022 at 7:53