the spoon is a familiar object, perhaps even intimate.  it is often our first tool, certainly most children's first eating utensil.  we imagine this to be the case because of the spoon's round, blunted head - not sharp like a knife, not pointed like a fork.

we see in the spoon a natural form, according to petrovsky and common sense;  i.e. the cupped hand, the shell.  unfortunately, the use of these implements unaugmented entails dipping the fingers into the to-be-ladled, so petrovsky reckons the addition here of a handle.  

if we adhere to this silverware expert's surmised origin, we describe a spoon as a shell with a handle.  certainly most spoons have this shape: round and then long.

certain variations include triangular-shaped heads, squarish heads; for whatever reason these have not caught on - I imagine the mouth to be more accepting of a round intruder than a cornered or pointy one.  also, the shape of the spoon mirrors that of the bowl, though often elongated to fit better into one's oralfice.

there is another variation, this one jeopardizes its right to be called a spoon, and so has another name: the spork.  employed popularly by kentucky fried chicken, the spork is a spoon, round and handled, with tines like a fork.  the surface of the ladle part is concave, and the tines follow that shape.  a hybrid of the two most-used silverwares, aside from camping, the spork is poorly represented in most dining situations.  it certainly has little chance of replacing the spoon.  this might be attributed to the spork's likely failure to facilitate ample cereal and soup consumption.  aside from its serving function, the spoon functions most often to transport liquid, occasionally chunk-laden, to the mouth.  while the spork could indeed fill this role, leaking some through it's tines, so too might an eighteen-inch metal ruler; it's a question of efficacy.  

so what is not a spoon - a spork, a fork, other handled implements with a point or points.  either of the component parts of a spoon, the handle or a small bowl are not a spoon.

a spoon must transport liquid.  a spoon must allow your hands to stay clear of the food.  a spoon need not fit in the mouth, some spoons are "serving spoons," larger to ladle out portions.

perhaps a look at the verb "to spoon" : spooning is kissing, making out, cars parked late at night in isolated places.  spooning is called thus because of the ways human bodies fit together, back to front?  this is not the typical necking position (though a pleasurable one for more serious coupling, to be sure).  according to webster's, this verbiage perhaps comes from the welsh custom of an engaged man's presenting his fiancee with an elaborately carved wooden spoon, symbolizing perhaps serving, nourishment, semen, utility, craftsmanship and homemaking.