In reality - no difference. Both are oaths and affirmations either directly or indirectly before a tribunal and/or in a court
proceeding. As such - knowingly giving false information is perjury.
In fact, that's why one has to be very careful when they are being deposed - that during the trial
of the matter they can be impeached and it shown that they knowingly lied during the deposition. Then a judge must (or should) take immediate action and hold them for criminal
Perjury is a criminal offense as determined by the underlying event that they are giving false testimony about.
Perjury, also known as forswearing, lying under oath or lying on oath, is the willful act of swearing a false oath or affirmation to tell the truth, whether spoken or in writing, concerning matters material to a judicial proceeding. That is, the witness falsely promises to tell the truth about matters which affect the outcome of the case. For example, it is not considered perjury to lie about one's age unless age is a factor in determining the legal result, such as eligibility for old age retirement benefits.
Perjury is considered a serious offense as it can be used to usurp the power of the courts, resulting in miscarriages of justice. In the United States, for example, the general perjury statute under Federal law defines perjury as a felony and provides for a prison sentence of up to five years.
The rules for perjury also apply when a person has made a statement under penalty of perjury, even if the person has not been sworn or affirmed as a witness before an appropriate official. An example of this is the United States' income tax return, which, by law, must be signed as true and correct under penalty of perjury (see U.S.C. § 6065).
Federal tax law provides criminal penalties of up to three years in prison for violation of the tax return perjury statute. See 26 U.S.C. § 7206(1).
Statements of interpretation of fact are not perjury because people often make inaccurate statements unwittingly and not deliberately. Individuals may have honest but mistaken beliefs about certain facts, or their recollection may be inaccurate. Like most other crimes in the common law system, to be convicted of perjury one must have had the intention (mens rea) to commit the act, and to have actually committed the act (actus reus). Subornation of perjury, attempting to induce another person to perjure themselves, is itself a crime.