What is an Earth Word™?

Question

_{This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles.}

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The Earth is composed with many various elements or objects.
But some of them belong to the Earth Word™, some of them don't.

If a word conforms to a special rule, I call it an Earth Word™.
Use the following examples below to find the rule.

$$ % set Title text. (spaces around the text ARE important; do not remove.) % increase Pad value only if your entries are longer than the title bar. % \def\Pad{\P{1.0}} \def\Title{\textbf{ Earth }} % \def\S#1#2{\Space{#1}{20px}{#2px}}\def\P#1{\V{#1em}}\def\V#1{\S{#1}{9}} \def\T{\Title\textbf{Words}^{\;\!™}\Pad}\def\NT{\Pad\textbf{Not}\T\ }\displaystyle \smash{\lower{29px}\bbox[yellow]{\phantom{\rlap{rubio.2019.05.15}\S{6px}{0} \begin{array}{cc}\Pad\T&\NT\\\end{array}}}}\atop\def\V#1{\S{#1}{5}} \begin{array}{|c|c|}\hline\Pad\T&\NT\\\hline % \text{ BANANA }&\text{ APPLE }\\ \hline \text{ SOUTH }&\text{ NORTH }\\ \hline \text{ AMERICA }&\text{ CANADA }\\ \hline \text{ SOCCER }&\text{ FOOTBALL }\\ \hline \text{ SPIN }&\text{ ROTATE }\\ \hline \text{ HOMOGENEOUS }&\text{ HETEROGENEOUS }\\ \hline \text{ COSTCO }&\text{ WALMART }\\ \hline \text{ WINDOWS }&\text{ LINUX }\\ \hline \text{ FEBRUARY }&\text{ JANUARY }\\ \hline \text{ ACCEPT }&\text{ DECLINE }\\ \hline \end{array}$$

Answer 1

An Earth word is a word which:

can be made entirely from symbols of elements in the Periodic Table.

As follows:

BANANA = Ba + Na + Na
SOUTH = S + O + U + Th
AMERICA = Am + Er + I + Ca
SOCCER = S + O + C + C + Er
SPIN = S + P + In (or S + P + I + N)
HOMOGENEOUS = Ho + Mo + Ge + Ne + O + U + S
COSTCO = C + O + S + Tc + O
WINDOWS = W + I + Nd + O + W + S
FEBRUARY = Fe + Br + U (or B + Ru) + Ar + Y
ACCEPT = Ac + Ce + Pt

The non-Earth words fail because of the following reasons:

APPLE - there is no 'Pl', 'L' or 'Le' element to get the L;
NORTH - there is no 'Or', 'R' or 'Rt' element to get the R;
CANADA - there is no 'Ad' or 'Da' element to get the D;
FOOTBALL - there is no 'L' element to get the final L;
ROTATE - there is no 'R' or 'Ro' element to get the R;
HETEROGENEOUS - if beginning He + Te, there is no 'Ro' element; if attempting to use 'Er' instead, there is no 'Et' or 'T' element to get the T;
WALMART - there is no 'Rt' or 'T' element to get the T;
LINUX - there is no 'Ux' or 'X' element to get the X;
JANUARY - no elements begin with a 'J';
DECLINE - there is no 'D' or 'De' element to get the 'D'.

There is a nod to the solution in the question since:

The Earth is composed with many various elements

Plus, regarding the name:

'Earth' is one of the four classic elements (along with air, water and fire).