<table class="table1">
    <tbody>
        <tr>
            <td>Something</td>
        </tr>
    </tbody>
</table>

<table class="table2">
    <tbody>
        <tr>
            <td>Something else</td>
        </tr>
    </tbody>
</table>

.table1 tbody td, .table2 tbody td{...}

(.table1, .table2) tbody td{...}