psi
Abbreviation with 3 meanings
| Stands for | Pounds per square inch |
|---|---|
| Meanings | 3 |
| Categories | Units & Measurements, Science & Engineering, Law & Legal |
| Also written | PSI |
psi has three meanings. The most common are Pounds per square inch (engineering unit) and Processing Speed Index (psychology); it can also stand for Presentence investigation.
Meanings of psi at a glance
| # | psi stands for | Context |
|---|---|---|
| 1 | Pounds per square inch | Units & Measurements › Engineering Unit |
| 2 | Processing Speed Index | Science & Engineering › Psychology |
| 3 | Presentence investigation | Law & Legal › Criminal Law |
1. Pounds per square inch
Units & Measurements · Engineering Unit Abbreviations
The US customary unit of pressure for tire inflation, air compressors, water pressure, scuba tanks and hydraulics. Car tires usually run at 30 to 35 psi, while road bike tires may use 80 to 100 psi.
Example: Inflate the tires to 35 psi when cold, as listed on the driver's door placard.
One psi is about 6.895 kPa, and standard atmospheric pressure is 14.7 psi. Tire readings are gauge pressure, above atmospheric; engineers distinguish psig (gauge) from psia (absolute). Scuba tanks hold about 3,000 psi, household water pressure is usually 40 to 80 psi, and US concrete is specified by strength in psi, as in a 4,000 psi mix.
2. Processing Speed Index (PSI)
Science & Engineering · Psychology Abbreviations
Wechsler index score measuring how quickly and accurately a person can scan, compare and record simple visual information, using timed subtests such as Coding and Symbol Search. Processing speed often slows with age and with many neurological conditions.
Example: A low PSI explained why he ran out of time on exams despite understanding the material.
PSI tends to be the index most affected by motor difficulties, fatigue and illness. Students with low processing speed may qualify for extended test time. In engineering psi is also a unit of pressure, pounds per square inch, written in lowercase.
3. Presentence investigation (PSI)
Law & Legal · Criminal Law Abbreviations
Investigation and report prepared by a probation officer before sentencing in state courts, covering the offense, criminal history, family, employment, health, substance use and victim impact, often with a sentencing recommendation. Judges rely heavily on it in choosing the sentence.
Example: Sentencing was set for August so probation could complete the PSI and interview the victims.
PSI and PSR (presentence report) are often used interchangeably, though federal courts usually say PSR. Defendants generally may review the report and object to inaccuracies, which can otherwise follow them into prison classification and parole decisions. Some states allow the PSI to be waived in negotiated plea cases.
Related abbreviations
More engineering unit abbreviations
- Pa – Pascal
- ppb – Parts per billion
- ppm – Parts per million
- PS – Pferdestärke (metric horsepower)
- psia – Pounds per square inch absolute
- psig – Pounds per square inch gauge
- R – Degree Rankine
- rad – Rad (radiation absorbed dose)
See all 103 engineering unit abbreviations →
More psychology abbreviations
- OCEAN – Openness, conscientiousness, extraversion, agreeableness, neuroticism
- PAI – Personality Assessment Inventory
- PERMA – Positive emotion, engagement, relationships, meaning, accomplishment
- PHQ-9 – Patient Health Questionnaire-9
- RT – Reaction time
- SB5 – Stanford-Binet Intelligence Scales, Fifth Edition
- SDT – Self-determination theory
- SEM – Structural equation modeling
See all 62 psychology abbreviations →
This entry is for general education and is not legal advice. Abbreviation use varies between institutions; always confirm in context.