This is what Ayn Rand wrote, correctly, about alturism:

"What is the moral code of altruism? The basic principle of altruism is that man has no right to exist for his own sake, that service to others is the only justification of his existence, and that self-sacrifice is his highest moral duty, virtue and value.

"Do not confuse altruism with kindness, good will or respect for the rights of others. These are not primaries, but consequences, which, in fact, altruism makes impossible. The irreducible primary of altruism, the basic absolute, is self-sacrifice—which means; self-immolation, self-abnegation, self-denial, self-destruction—which means: the self as a standard of evil, the selfless as a standard of the good.

"Do not hide behind such superficialities as whether you should or should not give a dime to a beggar. That is not the issue. The issue is whether you do or do not have the right to exist without giving him that dime. The issue is whether you must keep buying your life, dime by dime, from any beggar who might choose to approach you. The issue is whether the need of others is the first mortgage on your life and the moral purpose of your existence. The issue is whether man is to be regarded as a sacrificial animal. Any man of self-esteem will answer: 'No.' Altruism says: 'Yes.'”

from “Faith and Force: The Destroyers of the Modern World,” in the anthology Philosophy: Who Needs It

and

"There are two moral questions which altruism lumps together into one 'package-deal': (1) What are values? (2) Who should be the beneficiary of values? Altruism substitutes the second for the first; it evades the task of defining a code of moral values, thus leaving man, in fact, without moral guidance."

"Altruism declares that any action taken for the benefit of others is good, and any action taken for one’s own benefit is evil. Thus the beneficiary of an action is the only criterion of moral value—and so long as that beneficiary is anybody other than oneself, anything goes."

from “Introduction”, The Virtue of Selfishness

There are more excerpts at http://aynrandlexicon.com/lexicon/altrui...

"The Virtue of Selfishness is a collection of essays presenting Ayn Rand’s radical moral code of rational selfishness and its opposition to the prevailing morality of altruism—i.e., to the duty to sacrifice for the sake of others."

And noting that Comte explicitly sought to wipe causality out of philosophy, it is important to understand Ayn Rand's explanation of the role of causality and rejection of duty in ethics: “Causality Versus Duty,” in her anthology Philosophy: Who Needs It. http://aynrandlexicon.com/lexicon/duty.h...

This is what Comte himself wrote about his concept of altruism as an ethical standard in his Catechisme Positiviste (Catechism of Positivism), 1852:

"Positivism alone holds at once both a noble and true language when it urges us to live for others. This, the definitive formula of human morality, gives a direct sanction exclusively to our instincts of benevolence, the common source of happiness and duty. Implicitly and indirectly it sanctions our personal instincts, as the necessary conditions of our existence, with the proviso that they must be subordinate to those of altruism. With this limitation, we are even ordered to gratify our personal instincts, with the view of fitting ourselves to be better servants of Humanity, whose we are entirely." p313

"Positivism recognizes no right in anybody but the right to do his duty. To speak more accurately, our religion imposes on all the obligation to help every one to discharge his peculiar function. In politics we must eliminate Rights, as in philosophy we eliminate causes... All honest and sensible men, of whatever party, should agree, by a common consent, to eliminate the doctrin of rights. Positivism only recognizes duties, duties of all to all. Placing itself, as it does, at the social point of view, it cannot tolerate the notion of rights, for such notion rests on individualism. We are born under a load of obligations of every kind, to our predecessors, to our successors, to our contemporaries. After our birth these obligations increase or accumulate..." p331-2

from translation by R. Congreve, London: Kegan Paul, 1891
https://archive.org/details/catechismpos...

You are right that Ayn Rand used the full philosophical concept of altruism as formulated and popularized by Comte (1798-1857). Contrary to the falsehoods of Robbie53024's snide denuncations, it is not a "tortured definition", she did not "leave out the motivation", altruism does not mean "charity", and she did not "confuse it with slavery". Slavery is only one of the consequences of the altruist ethical standard that demands duty to live for others as the fundamental principle, in direct opposition to egoism.

From Webster's Dictionary Unabridged, 2nd ed, 1979:

Altruism, n. [Fr. altuisme, from It. altrui, of or to others, from L. alter, another. A term first emplyed by the Positivists, or followers of the French philosopher Comte.] unselfish concern for the welfare of others: opposed to egoism.

From the Dictionary of Philosophy, Runes, ed, 1962 edition:

Altruism: (Alter: other) In general, the cult of benevolence; the opposite of egoism. Term coined by Comte and adopted in Britain by H. Spencer.

For Comte Altruism meant the discipline and eradiction of self-centered desire, and a life devoted to the good of others; more particularly, selfless love and evotion to Society. In brief, it involved the self-abnegating love of Catholic Christianity redirected towards Humanity conceived as an ideal unity. As thus understood, altruism involves a conscious oppostion not only to egoism (whether understood as excessive or moderate self-love), but also to the formal or theological pursuit of charity and to the atomic or individualistic social philosophy of 17th-18th century liberalism, of utilitarianism, and of French Ideology.

She did study and learn from other philosophies--particularly what didn't work and what led to irrational and illogical behavior. Because some are taught from their earliest age that something is positive--even when shown that their learned definitions aren't right or even reasoned--they actually try to do the subversion.

All I was saying is that I am fully aware I may not know the definition of every word in our English language. This is particularly true when the progressive movement purposely bastardized the language by creating new meanings for words we all think we understand. This may be why news commentators now find the need to tell us what the President or Senate majority leader really said.