The second meaning has a narrower scope, and refers to the innominate contract
expressed in the phrase do ut des, that is, one thing is exchanged for a different one, both if the first is considered indeterminate as individual, but specifically or generically distinct, as if both are considered individually determinate.
From it follows that this deal may be admitted also by way of barter and by way of another innominate contract, as in I give so that you give me because from this follows that less money present is just barter, exchange, and equivalent to more money [that is] absent, (13) deducing everything much as the [issue] about buying has been worked out.
Because we concluded earlier (14) that none of these three said things may be proved by the law--rather, the opposite of them is in accordance with [the law]--we say that this deal, no more, no less, may be admitted by way of exchange, barter, or other innominate contract, as we have said earlier that it could be admitted by way of buying and selling.
We said [more] because if he decided to give it for the second and even for the third fair for what he would justly take until the payments of the first, then he can rightly do it, and it shall be a deed of charity and friendship; he would not be able to take more because [even if] what is given by way of true exchange or true interest may be given more expensively for two fairs than for one, and more expensively for three than for two, as was said above, (23) [this is not so] with the exchange by buying, bartering, or other innominate contract, which we refer to here.
In the fourth case, if he wanted to give them by way of buying, bartering, or other innominate contract of "I give so you give me," he would be able to take more for two reasons: because the merchant's money was absent and thus was worth less, and because the money was worth over there more than the money over here, as we have said above.
It is more of an innominate contract, which in many things differs from the above mentioned.
by buying, (23) bartering, or any other innominate contract
To exchange by buying, and by bartering or another innominate contract do not differ as far as this purpose is concerned .
Differences between the contract specifically provided for by the law 1 and an innominate contract, and similarities as far as this purpose is concerned .